Saturday, April 19, 2008

MFC Interview Question Part2

How do you find out if a linked-list has an end? (i.e. the list is not a cycle)

You can find out by using 2 pointers. One of them goes 2 nodes each time. The second one goes at 1 nodes each time. If there is a cycle, the one that goes 2 nodes each time will eventually meet the one that goes slower. If that is the case, then you will know the linked-list is a cycle.

What is the difference between realloc() and free()?

The free subroutine frees a block of memory previously allocated by the malloc subroutine. Undefined results occur if the Pointer parameter is not a valid pointer. If the Pointer parameter is a null value, no action will occur. The realloc subroutine changes the size of the block of memory pointed to by the Pointer parameter to the number of bytes specified by the Size parameter and returns a new pointer to the block. The pointer specified by the Pointer parameter must have been created with the malloc, calloc, or realloc subroutines and not been deallocated with the free or realloc subroutines. Undefined results occur if the Pointer parameter is not a valid pointer.

What is function overloading and operator overloading?

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Function overloading: C++ enables several functions of the same name to be defined, as long as these functions have different sets of parameters (at least as far as their types are concerned). This capability is called function overloading. When an overloaded function is called, the C++ compiler selects the proper function by examining the number, types and order of the arguments in the call. Function overloading is commonly used to create several functions of the same name that perform similar tasks but on different data types.
Operator overloading allows existing C++ operators to be redefined so that they work on objects of user-defined classes. Overloaded operators are syntactic sugar for equivalent function calls. They form a pleasant facade that doesn't add anything fundamental to the language (but they can improve understandability and reduce maintenance costs).

What is the difference between declaration and definition?

The declaration tells the compiler that at some later point we plan to present the definition of this declaration.
E.g.: void stars () //function declaration
The definition contains the actual implementation.
E.g.: void stars () // declarator
for(int j=10; j > =0; j--) //function body
cout << *; cout << head="="0)">next==0)
head->next = 0;
tail->next = head;
node* pre = head;
node* cur = head->next;
node* curnext = cur->next;
head->next = 0;
cur-> next = head;

for(; curnext!=0; )
cur->next = pre;
pre = cur;
cur = curnext;
curnext = curnext->next;

curnext->next = cur;

What is virtual constructors/destructors?
Virtual destructors:
If an object (with a non-virtual destructor) is destroyed explicitly by applying the delete operator to a base-class pointer to the object, the base-class destructor function (matching the pointer type) is called on the object.
There is a simple solution to this problem declare a virtual base-class destructor.
This makes all derived-class destructors virtual even though they don’t have the same name as the base-class destructor. Now, if the object in the hierarchy is destroyed explicitly by applying the delete operator to a base-class pointer to a derived-class object, the destructor for the appropriate class is called. Virtual constructor: Constructors cannot be virtual. Declaring a constructor as a virtual function is a syntax error.

Virtual destructors: If an object (with a non-virtual destructor) is destroyed explicitly by applying the delete operator to a base-class pointer to the object, the base-class destructor function (matching the pointer type) is called on the object.
There is a simple solution to this problem – declare a virtual base-class destructor. This makes all derived-class destructors virtual even though they don’t have the same name as the base-class destructor. Now, if the object in the hierarchy is destroyed explicitly by applying the delete operator to a base-class pointer to a derived-class object, the destructor for the appropriate class is called.

Virtual constructor: Constructors cannot be virtual. Declaring a constructor as a virtual function is a syntax error. Does c++ support multilevel and multiple inheritance?

What are the advantages of inheritance?
• It permits code reusability.
• Reusability saves time in program development.
• It encourages the reuse of proven and debugged high-quality software, thus reducing problem after a system becomes functional.

What is the difference between declaration and definition?
The declaration tells the compiler that at some later point we plan to present the definition of this declaration.
E.g.: void stars () //function declaration
The definition contains the actual implementation.
E.g.: void stars () // declarator
for(int j=10; j>=0; j--) //function body
cout<<”*”; cout<next;
pointer2 = pointer2->next; if (pointer2) pointer2=pointer2->next;
if (pointer1 == pointer2) {
print (\"circular\n\");

OK, why does this work?
If a list is circular, at some point pointer2 will wrap around and be either at the item just before pointer1, or the item before that. Either way, it’s either 1 or 2 jumps until they meet.

What do you mean by inline function?
The idea behind inline functions is to insert the code of a called function at the point where the function is called. If done carefully, this can improve the application's performance in exchange for increased compile time and possibly (but not always) an increase in the size of the generated binary executables.

Write a program that ask for user input from 5 to 9 then calculate the average
#include "iostream.h"
int main() {
int MAX = 4;
int total = 0;
int average;
int numb;
for (int i=0; i> numb;
while ( numb<5>9) {
cout << "Invalid input, please re-enter: "; cin >> numb;
total = total + numb;
average = total/MAX;
cout << "The average number is: " << i =" 1;" t =" *a;" a =" *b;" b =" t;" x =" a[5];" it =" list.begin()" i="="5)" x =" *it;">function_declaration; template function_declaration;
The only difference between both prototypes is the use of keyword class or typename, its use is indistinct since both expressions have exactly the same meaning and behave exactly the same way.

Define a constructor - What it is and how it might be called (2 methods).
constructor is a member function of the class, with the name of the function being the same as the class name. It also specifies how the object should be initialized.

Ways of calling constructor:
1) Implicitly: automatically by complier when an object is created.
2) Calling the constructors explicitly is possible, but it makes the code unverifiable.

class Point2D{
int x; int y;
public Point2D() : x(0) , y(0) {} //default (no argument) constructor


Point2D MyPoint; // Implicit Constructor call. In order to allocate memory on stack, the default constructor is implicitly called.

Point2D * pPoint = new Point2D(); // Explicit Constructor call. In order to allocate memory on HEAP we call the default constructor.

You have two pairs: new() and delete() and another pair : alloc() and free().
Explain differences between eg. new() and malloc()
1.) “new and delete” are preprocessors while “malloc() and free()” are functions. [we dont use brackets will calling new or delete].
2.) no need of allocate the memory while using “new” but in “malloc()” we have to use “sizeof()”.
3.) “new” will initlize the new memory to 0 but “malloc()” gives random value in the new alloted memory location [better to use calloc()]

new() allocates continous space for the object instace
malloc() allocates distributed space.
new() is castless, meaning that allocates memory for this specific type,
malloc(), calloc() allocate space for void * that is cated to the specific class type pointer.

What is the difference between class and structure?
Structure: Initially (in C) a structure was used to bundle different type of data types together to perform a particular functionality. But C++ extended the structure to contain functions also. The major difference is that all declarations inside a structure are by default public.
Class: Class is a successor of Structure. By default all the members inside the class are private.

What is RTTI?
Runtime type identification (RTTI) lets you find the dynamic type of an object when you have only a pointer or a reference to the base type. RTTI is the official way in standard C++ to discover the type of an object and to convert the type of a pointer or reference (that is, dynamic typing). The need came from practical experience with C++. RTTI replaces many Interview Questions - Homegrown versions with a solid, consistent approach.

What is encapsulation?
Packaging an object’s variables within its methods is called encapsulation.

Explain term POLIMORPHISM and give an example using eg. SHAPE object: If I have a base class SHAPE, how would I define DRAW methods for two objects CIRCLE and SQUARE

POLYMORPHISM : A phenomenon which enables an object to react differently to the same function call.
in C++ it is attained by using a keyword virtual

public class SHAPE
public virtual void SHAPE::DRAW()=0;
Note here the function DRAW() is pure virtual which means the sub classes must implement the DRAW() method and SHAPE cannot be instatiated

public class CIRCLE::public SHAPE
public void CIRCLE::DRAW()
// TODO drawing circle
public class SQUARE::public SHAPE
public void SQUARE::DRAW()
// TODO drawing square
now from the user class the calls would be like
SHAPE *newShape;

When user action is to draw
public void MENU::OnClickDrawCircle(){
newShape = new CIRCLE();

public void MENU::OnClickDrawCircle(){
newShape = new SQUARE();


the when user actually draws
public void CANVAS::OnMouseOperations(){

class SHAPE{
public virtual Draw() = 0; //abstract class with a pure virtual method

class CIRCLE{
public int r;
public virtual Draw() { this->drawCircle(0,0,r); }

class SQURE
public int a;
public virtual Draw() { this->drawRectangular(0,0,a,a); }

Each object is driven down from SHAPE implementing Draw() function in its own way.

What is an object?
Object is a software bundle of variables and related methods. Objects have state and behavior.

How can you tell what shell you are running on UNIX system?
You can do the Echo $RANDOM. It will return a undefined variable if you are from the C-Shell, just a return prompt if you are from the Bourne shell, and a 5 digit random numbers if you are from the Korn shell. You could also do a ps -l and look for the shell with the highest PID.

What do you mean by inheritance?
Inheritance is the process of creating new classes, called derived classes, from existing classes or base classes. The derived class inherits all the capabilities of the base class, but can add embellishments and refinements of its own

Describe PRIVATE, PROTECTED and PUBLIC – the differences and give examples.
class Point2D{
int x; int y;

public int color;
protected bool pinned;
public Point2D() : x(0) , y(0) {} //default (no argument) constructor

Point2D MyPoint;

You cannot directly access private data members when they are declared (implicitly) private:

MyPoint.x = 5; // Compiler will issue a compile ERROR
//Nor yoy can see them:
int x_dim = MyPoint.x; // Compiler will issue a compile ERROR

On the other hand, you can assign and read the public data members:

MyPoint.color = 255; // no problem
int col = MyPoint.color; // no problem

With protected data members you can read them but not write them: MyPoint.pinned = true; // Compiler will issue a compile ERROR

bool isPinned = MyPoint.pinned; // no problem

What is namespace?
Namespaces allow us to group a set of global classes, objects and/or functions under a name. To say it somehow, they serve to split the global scope in sub-scopes known as namespaces.
The form to use namespaces is:
namespace identifier { namespace-body }
Where identifier is any valid identifier and namespace-body is the set of classes, objects and functions that are included within the namespace. For example:
namespace general { int a, b; } In this case, a and b are normal variables integrated within the general namespace. In order to access to these variables from outside the namespace we have to use the scope operator ::. For example, to access the previous variables we would have to put:
general::a general::b
The functionality of namespaces is specially useful in case that there is a possibility that a global object or function can have the same name than another one, causing a redefinition error.

What is a COPY CONSTRUCTOR and when is it called?
A copy constructor is a method that accepts an object of the same class and copies it’s data members to the object on the left part of assignement:

class Point2D{
int x; int y;

public int color;
protected bool pinned;
public Point2D() : x(0) , y(0) {} //default (no argument) constructor
public Point2D( const Point2D & ) ;

Point2D::Point2D( const Point2D & p )
this->x = p.x;
this->y = p.y;
this->color = p.color;
this->pinned = p.pinned;

Point2D MyPoint;
MyPoint.color = 345;
Point2D AnotherPoint = Point2D( MyPoint ); // now AnotherPoint has color = 345

What is Boyce Codd Normal form?
A relation schema R is in BCNF with respect to a set F of functional dependencies if for all functional dependencies in F+ of the form a-> , where a and b is a subset of R, at least one of the following holds:
* a- > b is a trivial functional dependency (b is a subset of a)
* a is a superkey for schema R

What is virtual class and friend class?
Friend classes are used when two or more classes are designed to work together and need access to each other's implementation in ways that the rest of the world shouldn't be allowed to have. In other words, they help keep private things private. For instance, it may be desirable for class DatabaseCursor to have more privilege to the internals of class Database than main() has.

What is the word you will use when defining a function in base class to allow this function to be a polimorphic function?

What do you mean by binding of data and functions?

What’s the output of the following program? Why?
typedef union
int a;
char b[10];
float c;

Union x,y = {100};
x.a = 50;
x.c = 21.50;

printf(\"Union x : %d %s %f \n\",x.a,x.b,x.c );
printf(\"Union y :%d %s%f \n\",y.a,y.b,y.c);

Given inputs X, Y, Z and operations and & (meaning bitwise OR and AND, respectively)
What is output equal to in
output = (X & Y) (X & Z) (Y & Z)

Why are arrays usually processed with for loop?
The real power of arrays comes from their facility of using an index variable to traverse the array, accessing each element with the same expression a[i]. All the is needed to make this work is a iterated statement in which the variable i serves as a counter, incrementing from 0 to a.length -1. That is exactly what a loop does.

What is an HTML tag?
Answer: An HTML tag is a syntactical construct in the HTML language that abbreviates specific instructions to be executed when the HTML script is loaded into a Web browser. It is like a method in Java, a function in C++, a procedure in Pascal, or a subroutine in FORTRAN.

Explain which of the following declarations will compile and what will be constant - a pointer or the value pointed at: * const char *
* char const *
* char * const

Note: Ask the candidate whether the first declaration is pointing to a string or a single character. Both explanations are correct, but if he says that it’s a single character pointer, ask why a whole string is initialized as char* in C++. If he says this is a string declaration, ask him to declare a pointer to a single character. Competent candidates should not have problems pointing out why const char* can be both a character and a string declaration, incompetent ones will come up with invalid reasons.

You’re given a simple code for the class Bank Customer. Write the following functions:
* Copy constructor
* = operator overload
* == operator overload
* + operator overload (customers’ balances should be added up, as an example of joint account between husband and wife)

Note:Anyone confusing assignment and equality operators should be dismissed from the interview. The applicant might make a mistake of passing by value, not by reference. The candidate might also want to return a pointer, not a new object, from the addition operator. Slightly hint that you’d like the value to be changed outside the function, too, in the first case. Ask him whether the statement customer3 = customer1 + customer2 would work in the second case.

What problems might the following macro bring to the application?
#define sq(x) x*x

Anything wrong with this code?
T *p = new T[10];
delete p;

Everything is correct, Only the first element of the array will be deleted”, The entire array will be deleted, but only the first element destructor will be called.

Anything wrong with this code?
T *p = 0;
delete p;

Yes, the program will crash in an attempt to delete a null pointer.

How do you decide which integer type to use?
It depends on our requirement. When we are required an integer to be stored in 1 byte (means less than or equal to 255) we use short int, for 2 bytes we use int, for 8 bytes we use long int.

A char is for 1-byte integers, a short is for 2-byte integers, an int is generally a 2-byte or 4-byte integer (though not necessarily), a long is a 4-byte integer, and a long long is a 8-byte integer

What does extern mean in a function declaration?
Using extern in a function declaration we can make a function such that it can used outside the file in which it is defined.

An extern variable, function definition, or declaration also makes the described variable or function usable by the succeeding part of the current source file. This declaration does not replace the definition. The declaration is used to describe the variable that is externally defined.

If a declaration for an identifier already exists at file scope, any extern declaration of the same identifier found within a block refers to that same object. If no other declaration for the identifier exists at file scope, the identifier has external linkage.

What can I safely assume about the initial values of variables which are not explicitly initialized?
It depends on complier which may assign any garbage value to a variable if it is not initialized.

What is the difference between char a[] = “string”; and char *p = “string”;?
In the first case 6 bytes are allocated to the variable a which is fixed, where as in the second case if *p is assigned to some other value the allocate memory can change.

What’s the auto keyword good for?
Not much. It declares an object with automatic storage duration. Which means the object will be destroyed at the end of the objects scope. All variables in functions that are not declared as static and not dynamically allocated have automatic storage duration by default.

For example
int main()
int a; //this is the same as writing “auto int a;”

Local variables occur within a scope; they are “local” to a function. They are often called automatic variables because they automatically come into being when the scope is entered and automatically go away when the scope closes. The keyword auto makes this explicit, but local variables default to auto auto auto auto so it is never necessary to declare something as an auto auto auto auto.

What is the difference between char a[] = “string”; and char *p = “string”; ?
a[] = “string”;
char *p = “string”;

The difference is this:
p is pointing to a constant string, you can never safely say
however you can always say a[3]=’x';

char a[]=”string”; - character array initialization.
char *p=”string” ; - non-const pointer to a const-string.( this is permitted only in the case of char pointer in C++ to preserve backward compatibility with C.)

a[] = “string”;
char *p = “string”;

a[] will have 7 bytes. However, p is only 4 bytes. P is pointing to an adress is either BSS or the data section (depending on which compiler — GNU for the former and CC for the latter).

char a[] = “string”;
char *p = “string”;

for char a[]…….using the array notation 7 bytes of storage in the static memory block are taken up, one for each character and one for the terminating nul character.

But, in the pointer notation char *p………….the same 7 bytes required, plus N bytes to store the pointer variable “p” (where N depends on the system but is usually a minimum of 2 bytes and can be 4 or more)……

How do I declare an array of N pointers to functions returning pointers to functions returning pointers to characters?
If you want the code to be even slightly readable, you will use typedefs.
typedef char* (*functiontype_one)(void);
typedef functiontype_one (*functiontype_two)(void);
functiontype_two myarray[N]; //assuming N is a const integral

char* (* (*a[N])())()
Here a is that array. And according to question no function will not take any parameter value.

What does extern mean in a function declaration?
It tells the compiler that a variable or a function exists, even if the compiler hasn’t yet seen it in the file currently being compiled. This variable or function may be defined in another file or further down in the current file.

How do I initialize a pointer to a function?
This is the way to initialize a pointer to a function
void fun(int a)


void main()
void (*fp)(int);


How do you link a C++ program to C functions?
By using the extern "C" linkage specification around the C function declarations.

Explain the scope resolution operator.
It permits a program to reference an identifier in the global scope that has been hidden by another identifier with the same name in the local scope.

What are the differences between a C++ struct and C++ class?
The default member and base-class access specifier are different.

How many ways are there to initialize an int with a constant?
There are two formats for initializers in C++ as shown in the example that follows. The first format uses the traditional C notation. The second format uses constructor notation.
int foo = 123;
int bar (123);

How does throwing and catching exceptions differ from using setjmp and longjmp?
The throw operation calls the destructors for automatic objects instantiated since entry to the try block.

What is a default constructor?
Default constructor WITH arguments class B { public: B (int m = 0) : n (m) {} int n; }; int main(int argc, char *argv[]) { B b; return 0; }

What is a conversion constructor?
A constructor that accepts one argument of a different type.

What is the difference between a copy constructor and an overloaded assignment operator?
A copy constructor constructs a new object by using the content of the argument object. An overloaded assignment operator assigns the contents of an existing object to another existing object of the same class.

When should you use multiple inheritance?
There are three acceptable answers: "Never," "Rarely," and "When the problem domain cannot be accurately modeled any other way."

Explain the ISA and HASA class relationships. How would you implement each in a class design?
A specialized class "is" a specialization of another class and, therefore, has the ISA relationship with the other class. An Employee ISA Person. This relationship is best implemented with inheritance. Employee is derived from Person. A class may have an instance of another class. For example, an employee "has" a salary, therefore the Employee class has the HASA relationship with the Salary class. This relationship is best implemented by embedding an object of the Salary class in the Employee class.

When is a template a better solution than a base class?
When you are designing a generic class to contain or otherwise manage objects of other types, when the format and behavior of those other types are unimportant to their containment or management, and particularly when those other types are unknown (thus, the generosity) to the designer of the container or manager class.

What is a mutable member?
One that can be modified by the class even when the object of the class or the member function doing the modification is const.

What is an explicit constructor?
A conversion constructor declared with the explicit keyword. The compiler does not use an explicit constructor to implement an implied conversion of types. It’s purpose is reserved explicitly for construction

MFC Interview Question

Microsoft Technologies Interview Questions[MFC Interview Questions]

Can you explain the Document-View architecture in MFC ?
The document view architecture was introduced in MFC 2.0. In this architecture the application’s data is represented as a “document” object and the views of this data are represented as “view” objects. E.g. If you create an excel document what you see to get your job done i.e. cells, values, etc comprises the view and when you save this data it gets saved as a document. The various views of this document is as a table, graphs, bar charts, etc. The data is stored in a document object. The class representing the document object is CDocument. The sole purpose of this class is to manage an application’s data. Views server two purposes: renders visual representation of data stored in document and translate the user’s inputs into commands that operate on the data in the document. The class for view is CView. Thus the division of work in terms of data and view helps in work division, better productivity and reusability of code. There are two types of document/view applications:
SDI (Single Document Interface): This supports just a single open document at a time.
E.g. Wordpad, Notepad. If the user wants to open multiple documents then he has to open multiple instances of wordpad/notepad.
MDI (Multiple Document Interface): Supports multiple documents and multiple views of a document. An application is MDI if the user can open multiple documents in the same application instance.
E.g. Microsoft Word: The user can open multiple documents within a single instance of Ms Word.

Explain the difference between a modal and a modeless dialog box with an example of how to use them ?
A dialog box is a window that pops up in response to user action to inform the user with a message. E.g. if the user does not save the document and exists the application the window pops up asking if he wants to save the document. This window is the dialog box. Modal Dialog: A modal dialog box disables the window to which it is assigned until the user dismisses the dialog box. E.g. The dialog that gets displayed with “yes”/”no”/”cancel” when you try to exit MS Word without saving the document is a modal dialog box. A model dialog box is created by calling the doModal() function of the dialog class. This function does not return back control to the caller until the dialog is dismissed. E.g. CDialog dlg; dlg.doModal(); Modeless Dialog: A modeless dialog box is just the reverse of modal. It allows the user complete control of the application which owns it and the user can continue his work without closing the dialog. A modeless dialog box can be created using the Create () command of CDialog class. The Create() call returns as soon as the dialog box is created. Hence the control returns back to the caller and the user is able to continue using the application.

Which are the common dialogs in MFC and what is each used for ?
Common dialogs are those that appear so frequently in application programs and hence the have become a part of MFC library. MFC provides the common dialogs listed below: - CFileDialog: File Open and File Save As dialog - CPrintDialog: Print and Print Setup dialog - CPageSetupDialog: Page setup dialog - CFindReplaceDialog: File and replace dialog - CColorDialog: Color dialog box - CFontDialog: Dialog box to change font style, color, size, etc. A common dialog is invoked by filling in the fields of the data structure and then calling the doModal() of the dialog. When the dialog returns the user input values are populated in the respective fields of the data structure.E.g. Lets say we want to show the File Open dialog box. TCHAR filter [] = _T (“Text files (*.txt)*.txt”); //Specify a filer for the file type CFileDialog dlg(TRUE, _T(“txt”), _T(“*.txt”), OFN_FILEMUSTEXIST, filter); If(dlg.doModal() == IDOK){//Get the user selected file namefilename = dlg.GetFileName();}

What is GDI ?
GDI is an acronym for Graphics Device Interface. The GDI allows you to draw on your windows. It is a device independent output model in the sense that the graphics code that you write for drawing will work on any video output which has a Windows driver. In order to avoid one window interfering with another while drawing output on the screen GDI uses a mechanism called as device context to avoid this conflict. So when a window draws on a screen, printer or any other output device, it doesn’t output pixels directly on the device. Instead it draws to a logical surface represented by a “device context” (DC). A DC is a data structure that has all information that GDI needs to know. Before a Windows program draws anything on the screen it acquires a DC handle from the GDI and then passes this handle back to the GDI each time it calls the GDI output function. In MFC a DC encapsulates the GDI functions that a program uses to generate output. MFC’s CDC class wraps a Windows device context and the GDI functions into one package. CPaintDC and CClientDC are subclasses of CDC and represent the different types of device contexts that windows applications use. E.g. CDC* pDC = GetDC(); //do some drawing Release (pDC);

Which are the different ways of Thread Synchronization ?
In a multi threaded application each thread must coordinate its actions with other threads in the application. If two or more threads access a same resource then that resource needs to be synchronized so that all threads don’t try to modify it at the same time. Windows supports four types of synchronization objects that can be used to synchronize the actions performed by concurrently running multiple threads. - Critical Sections - Mutexes - Events - Semaphores Critical Section: These are used to serialize access to resources that are accessed by multiple threads. All the threads must belong to same process because critical sections won’t work across process boundaries. CCriticalSection is a class and CCriticalSection::Lock locks a critical section and CCriticalSection::UnLock unlocks it. E.g. CCriticalSection cs; //Thread T1 cs.Lock (); //access the shared resource cs.UnLock (); /Thread T2 cs.Lock (); /access the shared resource Cs.Unlock (); Mutexes: Serves the same purpose as critical sections but can be used to synchronize threads running in same process or across processes. CMutex is its corresponding class. Semaphores: They maintain resource counts representing the number of resources available. Locking a semaphore decrements resource count and unlocking increments it. A thread that tries to lock a semaphore with resource count 0 gets blocked until another thread unlocks the semaphore and increases the resource count. CSemaphore is a class representing semaphores.

What are property pages ? What are they used for ?
Property sheets are tabbed dialog boxes containing pages that the user can switch with mouse clicks. They are a part of common library of windows just like dialog and other controls. E.g. when a user adds a schedules task it walks him through a wizard which is nothing but a property sheet. The functionality of property sheets is encapsulated in MFC classes of CPropertySheet and CPropertyPage. CPropertyPage represents a page in a property sheet and is a subclass of CDialog. Like dialog boxes property sheets can be modal or modeless. Use CPropertySheet::DoModal for modal and CPropertySheet::Create for a modeless property sheet. There are four broad steps in creating a property page:
For each property page create a dialog template.
For the created dialog associate a class that derives from CPropertyPage.
Derive a property sheet class from CPropertySheet and create an object for each above created property pages.
Add the property page objects to the created property sheet using AddPage.
Call the doModal function of the property sheet to display it on the screen.

What are DLL’s and which are the different types of DLL’s ?
Dynamic link libraries (also called as DLL’s) are a very important part of windows. Most of the files associated with windows are either executables or DLL’s. Unlike executable which can be directly invokes, a DLL cannot be invoked directly. Instead a DLL is a set of files containing functions that can be called by other programs or other DLL’s to get the job done. Dynamic linking means the process that Windows uses to link a function call of one module to the actual function in the DLL. Linking is of two types: static and dynamic linking. Static Linking happens during program development time while dynamic linking happens at run time. One can create a DLL of resource only as well. DLL usually have an extension .DLL which is loaded by windows automatically when required however one can load DLL using LoadLibrary or LoadLibraryEx calls as well. The two types of DLL which one can make with MFC are:
Extension DLL: These DLL’s exposes variables and functions to the client application. It can expose C++ functions and C++ classes to be used in your application.
Regular DLL: MFC extension DLL’s can be used only with MFC applications. If you want a dll to be used by a wider range of applications then use a regular DLL.

Thursday, January 25, 2007

The 25 most difficult questions you'll be asked on a job interview

The 25 most difficult questions you'll be asked on a job interview

Being prepared is half the battle.

If you are one of those executive types unhappy at your present post and embarking on a New Year's resolution to find a new one, here's a helping hand. The job interview is considered to be the most critical aspect of every expedition that brings you face-to- face with the future boss. One must prepare for it with the same tenacity and quickness as one does for a fencing tournament or a chess match.

This article has been excerpted from "PARTING COMPANY: How to Survive the Loss of a Job and Find Another Successfully" by William J. Morin and James C. Cabrera. Copyright by Drake Beam Morin, inc. Publised by Harcourt Brace Jovanovich.
Morin is chairman and Cabrera is president of New York-based Drake Beam Morin, nation's major outplacement firm, which has opened offices in Philadelphia.

1. Tell me about yourself.
Since this is often the opening question in an interview, be extracareful that you don't run off at the mouth. Keep your answer to a minute or two at most. Cover four topics: early years, education, work history, and recent career experience. Emphasize this last subject. Remember that this is likely to be a warm-up question. Don't waste your best points on it.

2. What do you know about our organization?
You should be able to discuss products or services, revenues, reputation, image, goals, problems, management style, people, history and philosophy. But don't act as if you know everything about the place. Let your answer show that you have taken the time to do some research, but don't overwhelm the interviewer, and make it clear that you wish to learn more.
You might start your answer in this manner: "In my job search, I've investigated a number of companies.
Yours is one of the few that interests me, for these reasons..."
Give your answer a positive tone. Don't say, "Well, everyone tells me that you're in all sorts of trouble, and that's why I'm here", even if that is why you're there.

3. Why do you want to work for us?
The deadliest answer you can give is "Because I like people." What else would you like-animals?
Here, and throughout the interview, a good answer comes from having done your homework so that you can speak in terms of the company's needs. You might say that your research has shown that the company is doing things you would like to be involved with, and that it's doing them in ways that greatly interest you. For example, if the organization is known for strong management, your answer should mention that fact and show that you would like to be a part of that team. If the company places a great deal of emphasis on research and development, emphasize the fact that you want to create new things and that you know this is a place in which such activity is encouraged. If the organization stresses financial controls, your answer should mention a reverence for numbers.
If you feel that you have to concoct an answer to this question - if, for example, the company stresses research, and you feel that you should mention it even though it really doesn't interest you- then you probably should not be taking that interview, because you probably shouldn't be considering a job with that organization.
Your homework should include learning enough about the company to avoid approaching places where you wouldn't be able -or wouldn't want- to function. Since most of us are poor liars, it's difficult to con anyone in an interview. But even if you should succeed at it, your prize is a job you don't really want.

4. What can you do for us that someone else can't?
Here you have every right, and perhaps an obligation, to toot your own horn and be a bit egotistical. Talk about your record of getting things done, and mention specifics from your resume or list of career accomplishments. Say that your skills and interests, combined with this history of getting results, make you valuable. Mention your ability to set priorities, identify problems, and use your experience and energy to solve them.

5. What do you find most attractive about this position? What seems least attractive about it?
List three or four attractive factors of the job, and mention a single, minor, unattractive item.

6. Why should we hire you?
Create your answer by thinking in terms of your ability, your experience, and your energy. (See question 4.)

7. What do you look for in a job?
Keep your answer oriented to opportunities at this organization. Talk about your desire to perform and be recognized for your contributions. Make your answer oriented toward opportunity rather than personal security.

8. Please give me your defintion of [the position for which you are being interviewed].
Keep your answer brief and taskoriented. Think in in terms of responsibilities and accountability. Make sure that you really do understand what the position involves before you attempt an answer. If you are not certain. ask the interviewer; he or she may answer the question for you.

9. How long would it take you to make a meaningful contribution to our firm?
Be realistic. Say that, while you would expect to meet pressing demands and pull your own weight from the first day, it might take six months to a year before you could expect to know the organization and its needs well enough to make a major contribution.

10. How long would you stay with us?
Say that you are interested in a career with the organization, but admit that you would have to continue to feel challenged to remain with any organization. Think in terms of, "As long as we both feel achievement-oriented."

11. Your resume suggests that you may be over-qualified or too experienced for this position. What's Your opinion?
Emphasize your interest in establishing a long-term association with the organization, and say that you assume that if you perform well in his job, new opportunities will open up for you. Mention that a strong company needs a strong staff. Observe that experienced executives are always at a premium. Suggest that since you are so wellqualified, the employer will get a fast return on his investment. Say that a growing, energetic company can never have too much talent.

12. What is your management style?
You should know enough about the company's style to know that your management style will complement it. Possible styles include: task oriented (I'll enjoy problem-solving identifying what's wrong, choosing a solution and implementing it"), results-oriented ("Every management decision I make is determined by how it will affect the bottom line"), or even paternalistic ("I'm committed to taking care of my subordinates and pointing them in the right direction").
A participative style is currently quite popular: an open-door method of managing in which you get things done by motivating people and delegating responsibility.
As you consider this question, think about whether your style will let you work hatppily and effectively within the organization.

13. Are you a good manager? Can you give me some examples? Do you feel that you have top managerial potential?
Keep your answer achievementand ask-oriented. Rely on examples from your career to buttress your argument. Stress your experience and your energy.

14. What do you look for when You hire people?
Think in terms of skills. initiative, and the adaptability to be able to work comfortably and effectively with others. Mention that you like to hire people who appear capable of moving up in the organization.

15. Have you ever had to fire people? What were the reasons, and how did you handle the situation?
Admit that the situation was not easy, but say that it worked out well, both for the company and, you think, for the individual. Show that, like anyone else, you don't enjoy unpleasant tasks but that you can resolve them efficiently and -in the case of firing someone- humanely.

16. What do you think is the most difficult thing about being a manager or executive?
Mention planning, execution, and cost-control. The most difficult task is to motivate and manage employess to get something planned and completed on time and within the budget.

17. What important trends do you see in our industry?
Be prepared with two or three trends that illustrate how well you understand your industry. You might consider technological challenges or opportunities, economic conditions, or even regulatory demands as you collect your thoughts about the direction in which your business is heading.

18. Why are you leaving (did you leave) your present (last) job?
Be brief, to the point, and as honest as you can without hurting yourself. Refer back to the planning phase of your job search. where you considered this topic as you set your reference statements. If you were laid off in an across-the-board cutback, say so; otherwise, indicate that the move was your decision, the result of your action. Do not mention personality conflicts.
The interviewer may spend some time probing you on this issue, particularly if it is clear that you were terminated. The "We agreed to disagree" approach may be useful. Remember hat your references are likely to be checked, so don't concoct a story for an interview.

19. How do you feel about leaving all your benefits to find a new job?
Mention that you are concerned, naturally, but not panicked. You are willing to accept some risk to find the right job for yourself. Don't suggest that security might interest you more than getting the job done successfully.

20. In your current (last) position, what features do (did) you like the most? The least?
Be careful and be positive. Describe more features that you liked than disliked. Don't cite personality problems. If you make your last job sound terrible, an interviewer may wonder why you remained there until now.

21. What do you think of your boss?
Be as positive as you can. A potential boss is likely to wonder if you might talk about him in similar terms at some point in the future.

22. Why aren't you earning more at your age?
Say that this is one reason that you are conducting this job search. Don't be defensive.

23. What do you feel this position should pay?
Salary is a delicate topic. We suggest that you defer tying yourself to a precise figure for as long as you can do so politely. You might say, "I understand that the range for this job is between $______ and $______. That seems appropriate for the job as I understand it." You might answer the question with a question: "Perhaps you can help me on this one. Can you tell me if there is a range for similar jobs in the organization?"
If you are asked the question during an initial screening interview, you might say that you feel you need to know more about the position's responsibilities before you could give a meaningful answer to that question. Here, too, either by asking the interviewer or search executive (if one is involved), or in research done as part of your homework, you can try to find out whether there is a salary grade attached to the job. If there is, and if you can live with it, say that the range seems right to you.
If the interviewer continues to probe, you might say, "You know that I'm making $______ now. Like everyone else, I'd like to improve on that figure, but my major interest is with the job itself." Remember that the act of taking a new job does not, in and of itself, make you worth more money.
If a search firm is involved, your contact there may be able to help with the salary question. He or she may even be able to run interference for you. If, for instance, he tells you what the position pays, and you tell him that you are earning that amount now and would Like to do a bit better, he might go back to the employer and propose that you be offered an additional 10%.
If no price range is attached to the job, and the interviewer continues to press the subject, then you will have to restpond with a number. You cannot leave the impression that it does not really matter, that you'll accept whatever is offered. If you've been making $80,000 a year, you can't say that a $35,000 figure would be fine without sounding as if you've given up on yourself. (If you are making a radical career change, however, this kind of disparity may be more reasonable and understandable.)
Don't sell yourself short, but continue to stress the fact that the job itself is the most important thing in your mind. The interviewer may be trying to determine just how much you want the job. Don't leave the impression that money is the only thing that is important to you. Link questions of salary to the work itself.
But whenever possible, say as little as you can about salary until you reach the "final" stage of the interview process. At that point, you know that the company is genuinely interested in you and that it is likely to be flexible in salary negotiations.

24. What are your long-range goals?
Refer back to the planning phase of your job search. Don't answer, "I want the job you've advertised." Relate your goals to the company you are interviewing: 'in a firm like yours, I would like to..."

25. How successful do you you've been so far?
Say that, all-in-all, you're happy with the way your career has progressed so far. Given the normal ups and downs of life, you feel that you've done quite well and have no complaints.
Present a positive and confident picture of yourself, but don't overstate your case. An answer like, "Everything's wonderful! I can't think of a time when things were going better! I'm overjoyed!" is likely to make an interviewer wonder whether you're trying to fool him . . . or yourself. The most convincing confidence is usually quiet confidence.

As Reprinted from FOCUS Magazine -- January 5, 1983

Strengths and Weaknesses : Interview Question

Answers to the Toughest Interview Questions .

Why should we hire you?
What are your three greatest strengths?
What can you contribute to our organization?
Assume that you are a candidate in the coming general election. Tell me why you are the best candidate in the field.
What is your greatest strength?
We've interviewed a number of highly qualified students for this position. What sets you apart from the others?
What are your strengths?
What part of your current job are you the most comfortable with?
What are your strong points and how have they helped you to succeed?

What is your greatest weakness?
Name your three greatest weaknesses.
Which is the worst of your three greatest weaknesses and why?
What are your weaknesses?
What part of your current job are you the least comfortable with?
What are your weak points and how have you overcome them?
What about yourself would you want to improve
In which area do you need to make the improvement in?

What are some of the things you find difficult to do?

The interviewer is looking to determine how well you know yourself, how you react to difficult situations/tasks and credibility. Look back over your work experience for examples of challenges...speaking in public at a meeting, disagreeing with a manager over an important issue, being asked to use a software program you have not had an opportunity to learn...

C++ Interview Question Part One

C++ Interview Question:

1. Does a class provide default Copy Constructor?
Yes! The default copy constructor is being provided automatically by the compiler if not implemented separately. In this, it puts the code for coping the data members and other variables that stay in stack. If something is being created by malloc or new in the heap, those are not being copied by the default copy constructor provide by the compiler.

2. What does a default Copy Constructor do?
A default copy constructor is being provided by the compiler, when an attempt to copy an existing object is made. In this case the control goes to the default copy constructor. It generates a new object, and makes the values of data members of the new object which are in the stack, same as the parent object. It doesn’t copy the variables that are created in the heap. Simply speaking, a compiler supplied default copy constructor doesn’t take care of the things in an object, that are being created using malloc/calloc or new.

3. Can a program have a virtual constructor?
Generally we don’t need an overridable constructor. So constructor should not be declared as virtual. But in a class, we can make a static method, which will call the private/protected constructor and create an object. In that case the constructor is called as virtual constructor.

4. When does a programmer need to implement his own copy constructor?
Though compiler automatically provides the default copy constructor, sometime a programmer needs to implement his own copy constructor. We can take up a case here:
In the default constructor some memory allocation has been done for few data members and hence those will be created in the heap. In the destructor corresponding de-allocation code is there. Now if an attempt to copy an object is made, it won’t call the default constructor but it will call the default copy constructor which will copy the data member variable from stack and copy the pointers but won’t allocate any new memory space for the new copied object. So same pointers will exist in both the parent and copied object. This will not only create a great ambiguity but runtime error will occur when attempts will be made to delete both the objects. First object will get deleted properly. When it will try to delete the other object, the common pointer won’t exist and runtime error will come. Even if user stops the application it will try to delete all the objects in the memory and runtime error will occur. In a single word, copy constructor is needed to be implemented independently, when the parent object has some allocated memory in heap for some of its data member and that gets deleted by destructor. Copy constructor should consist that much of code for memory allocation for the newly created object.Apart from this, programmer can implement his own copy constructor to copy any other things, which he wants specifically.

5. Can a copy constructor accept an object of the same class as parameter, instead of reference of the object?
No. It is specified in the definition of the copy constructor itself. It should generate an error if a programmer specifies a copy constructor with a first argument that is an object and not a reference.
Logically thinking, if we can consider the same as copy constructor also, big confusion will come. If we pass an object as a function parameter, by value, it will get copied first and then be passed to the function. At the time of getting copied it should call the copy constructor. So in this case, if we consider the above described constructor as copy constructor, at the very beginning of the function call, it wil attempt to copy the object and hence again call the same function and hence will go towards an infinite loop. This will probably be ended up with an unexpected stack overflow.
It will give compiler error if an object of the same class is being passed to a constructor, but it doesn’t give error if more than one different objects are being passed to the constructor . In this case it doesn’t treat it as copy constructor, but a normal overloaded constructor.

6. What is the return parameter of a constructor and why?
Constructor in never being called directly. It is being called automatically by the compiler when an object in being created (or copied). Hence it can’t return any parameter. Logically thinking, if it would have been made to return a parameter, how do we put the code to create an object?

7. Are the “default constructor” and “constructor with default parameter” same?
Default constructor is a constructor, which can be called with no argument. So a constructor with all the parameters as default argument can be called as default constructor. A constructor with one or more default parameters (but not all the parameters) can be called “constructor with default parameter” but that won’t be the default constructor.
If a constructor with no argument and a constructor with all default arguments are being implemented then object-creation will generate an ambiguity regarding which constructor is to be called.