Ans : Released in 1985, C++ is an object-oriented programming language created by Bjarne Stroustrup. C++ maintains almost all aspects of the C language, while simplifying memory management and adding several features - including a new datatype known as a class (you will learn more about these later) - to allow object-oriented programming. C++ maintains the features of C which allowed for low-level memory access but also gives the programmer new tools to simplify memory management. C++ used for:
C++ is a powerful general-purpose programming language. It can be used to create small programs or large applications. It can be used to make CGI scripts or console-only DOS programs. C++ allows you to create programs to do almost anything you need to do. The creator of C++, Bjarne Stroustrup, has put together a partial list of applications written in C++.

Ans : 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.

Ans : 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.

If we initialize the base class pointer with derived object, calling of that virtual method will result in which method being called?
Ans : a. Base method
b. Derived method Ans. B

Ans : 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).

Ans : 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.

Ans : 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 << endl;
}

Ans : 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.

Ans : Public, protected and private are three access specifier in C++.
Public data members and member functions are accessible outside the class.
Protected data members and member functions are only available to derived classes.
Private data members and member functions can’t be accessed outside the class. However there is an exception can be using friend classes.

Ans : 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.

Ans : Yes.

Ans : • 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.

Ans : 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<<endl;
}

Ans : Templates allow to create generic functions that admit any data type as parameters and return value without having to overload the function with all the possible data types. Until certain point they fulfill the functionality of a macro. Its prototype is any of the two following ones: template <class indetifier> function_declaration; template <typename indetifier> 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.

Ans : 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
};
main(){}
}
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().

Ans : 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.

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.

Ans : 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).

Ans : Packaging an object’s variables within its methods is called encapsulation.

Ans : Object is a software bundle of variables and related methods. Objects have state and behavior.

Ans : 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.

Ans : 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.

Ans : 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.

Ans : 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.

Ans : virtual

Ans : Encapsulation.

Ans : 1. Taking a reference to the function from the DLL instance.
2. Using the DLL ’s Type Library

Ans : Classes and objects are separate but related concepts. Every object belongs to a class and every class contains one or more related objects.
- A Class is static. All of the attributes of a class are fixed before, during, and after the execution of a program. The attributes of a class don't change.
- The class to which an object belongs is also (usually) static. If a particular object belongs to a certain class at the time that it is created then it almost certainly will still belong to that class right up until the time that it is destroyed.
- An Object on the other hand has a limited lifespan. Objects are created and eventually destroyed. Also during that lifetime, the attributes of the object may undergo significant change.

Ans : Class is a user-defined data type in C++. It can be created to solve a particular kind of problem. After creation the user need not know the specifics of the working of a class.

Ans : As the name suggests, the function acts as a friend to a class. As a friend of a class, it can access its private and protected members. A friend function is not a member of the class. But it must be listed in the class definition.

Ans : Mergesort always makes recursive calls to sort subarrays that are about half size of the original array, resulting in O(n log n) time.

Ans : Abstraction is of the process of hiding unwanted details from the user.

Ans : A virtual function allows derived classes to replace the implementation provided by the base class. The compiler makes sure the replacement is always called whenever the object in question is actually of the derived class, even if the object is accessed by a base pointer rather than a derived pointer. This allows algorithms in the base class to be replaced in the derived class, even if users don't know about the derived class.

Ans : An internal iterator is implemented with member functions of the class that has items to step through. .An external iterator is implemented as a separate class that can be "attach" to the object that has items to step through. .An external iterator has the advantage that many difference iterators can be active simultaneously on the same object.

Ans : A scope resolution operator (::), can be used to define the member functions of a class outside the class.

Ans : A pure virtual member function is a member function that the base class forces derived classes to provide. Normally these member functions have no implementation. Pure virtual functions are equated to zero. class Shape { public: virtual void draw() = 0; };

Ans : "Poly" means "many" and "morph" means "form". Polymorphism is the ability of an object (or reference) to assume (be replaced by) or become many different forms of object. Example: function overloading, function overriding, virtual functions. Another example can be a plus ‘+’ sign, used for adding two integers or for using it to concatenate two strings.

Ans : 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.

Ans : 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.

Ans : * char const * * char * const

Ans : #define sq(x) x*x

Ans : 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.

Ans : T *p = 0;
delete p;
Yes, the program will crash in an attempt to delete a null pointer.

Ans : 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.

Ans : 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.

Ans : It depends on complier which may assign any garbage value to a variable if it is not initialized.

Ans : 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.

Ans : 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.

Ans : a[] = “string”;
char *p = “string”;
The difference is this:
p is pointing to a constant string, you can never safely say
p[3]=’x';
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.)

Ans : 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

Ans : 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.

Ans : By using the extern "C" linkage specification around the C function declarations.

Ans : 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.

Ans : The default member and base-class access specifier are different.

Ans : Two. 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);

Ans : The throw operation calls the destructors for automatic objects instantiated since entry to the try block.

Ans : 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; }

Ans : A constructor that accepts one argument of a different type.

Ans : An overloaded assignment operator assigns the contents of an existing object to another existing object of the same class.

Ans : There are three acceptable answers: "Never," "Rarely," and "When the problem domain cannot be accurately modeled any other way."

Ans : 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.

Ans : 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.

Ans : One that can be modified by the class even when the object of the class or the member function doing the modification is const.

Ans : 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.

Ans : A library of container templates approved by the ANSI committee for inclusion in the standard C++ specification. A programmer who then launches into a discussion of the generic programming model, iterators, allocators, algorithms, and such, has a higher than average understanding of the new technology that STL brings to C++ programming.

Ans : The ability to determine at run time the type of an object by using the typeid operator or the dynamic cast operator.

Ans : Multiple providers of libraries might use common global identifiers causing a name collision when an application tries to link with two or more such libraries. The namespace feature surrounds a library’s external declarations with a unique namespace that eliminates the potential for those collisions.
This solution assumes that two library vendors don’t use the same namespace identifier, of course.

Ans : Yes. The ANSI committee added the bool intrinsic type and its true and false value keywords.

Ans : A modifier, also called a modifying function is a member function that changes the value of at least one data member. In other words, an operation that modifies the state of an object. Modifiers are also known as ‘mutators’.

Ans : An accessor is a class operation that does not modify the state of an object. The accessor functions need to be declared as const operations

Ans : Template class: A generic definition or a parameterized class not instantiated until the client provides the needed information. It’s jargon for plain templates.
Class template: A class template specifies how individual classes can be constructed much like the way class specifies how individual objects can be constructed. It’s jargon for plain classes

Ans : A name clash occurs when a name is defined in more than one place. For example., two different class libraries could give two different classes the same name. If you try to use many class libraries at the same time, there is a fair chance that you will be unable to compile or link the program because of name clashes.

Ans : A dangling pointer arises when you use the address of an object after its lifetime is over. This may occur in situations like returning addresses of the automatic variables from a function or using the address of the memory block after it is freed.

Ans : Message:
Objects communicate by sending messages to each other.
A message is sent to invoke a method
Method:
Provides response to a message.
It is an implementation of an operation.

Ans : A class that has no functionality of its own. Its member functions hide the use of a third party software component or an object with the non-compatible interface or a non-object-oriented implementation.

Ans : It is an object of some class whose purpose is to indicate that a real object of that class does not exist. One common use for a null object is a return value from a member function that is supposed to return an object with some specified properties but cannot find such an object.

Ans : A class invariant is a condition that defines all valid states for an object. It is a logical condition to ensure the correct working of a class. Class invariants must hold when an object is created, and they must be preserved under all operations of the class. In particular all class invariants are both preconditions and post-conditions for all operations or member functions of the class.

Ans : It is a process during exception handling when the destructor is called for all local objects between the place where the exception was thrown and where it is caught.

Ans : Objects that stand for other objects are called proxy objects or surrogates.

Ans : Smalltalk, Java, Eiffel, Sather.

Ans : If two base classes have no overlapping methods or data they are said to be independent of, or orthogonal to each other. Orthogonal in the sense means that two classes operate in different dimensions and do not interfere with each other in any way. The same derived class may inherit such classes with no difficulty.

Ans : semaphore is used to synchronize processes. where as mutex is used to provide synchronization between threads running in the same process

Ans : Destructor usually deletes any extra resources allocated by the object.

Ans :
auto
register
static
extern
auto:the default. Variables are automatically created and initialized when they are defined and are destroyed at the end of the block containing their definition. They are not visible outside that block
register:a type of auto variable. a suggestion to the compiler to use a CPU register for performance
static:a variable that is known only in the function that contains its definition but is never destroyed and retains its value between calls to that function. It exists from the time the program begins execution
extern:a static variable whose definition and placement is determined when all object and library modules are combined (linked) to form the executable code file. It can be visible outside the file where it is defined.

Ans : reference is a name that acts as an alias, or alternative name, for a previously defined variable or an object.prepending variable with "&" symbol makes it as reference.
for example:
int a;
int &b = a;

Ans : The defining traits of an object-oriented langauge are:
encapsulation
inheritance
polymorphism

Ans : The Performance problem encountered by linear probing is caused by the cluster buildup That occurs as a result of the probing sequence. Quadratic probing uses a different sequence to avoid primary clustering.

Ans : The Chaining technique basically looks at the hash table as an array of pointers to linked lists. Each slot in the hash table is either empty or simply consists of a pointer to a linked list. You resolve collisions by adding the elements that hash to the same slot to the linked list to which that slot points. At the same time, deletions are easy, You simply delete elements from the linked list.

Ans : The hash function is an important part of the hashing technique. This function is used to transform the keys into table addresses. The hash function we choose should be easy to compute and should be able to transform the keys into integers in the range 0 to TR-1. Because most of the commonly used hash functions are based on arithmetic operations, We should convert the keys to numbers on which arithmetic operations can be performed

Ans : The visualization is the basically a way of presentation ,Its just a fancy name for the diagrams, pictures, screen shots, prototypes, and any other visual representations created to help through and design the graphical user interface of your product.

Ans : Inheritance is a basically can be private , public, or virtual. With virtual inheritance there is only one copy of each object even if the object appears more than once in the hierarchy.

Ans : Multithreading is defined as :It is the task of creating a new thread of execution within an existing process rather than starting a new process to begin a function. It is the ability of an operating system to concurrently run programs that have been divided into subcomponents, or threads.

Ans : Using is bassically a namespace scope. Its directive used to declare the accessibility of identifiers declared within a namespace scope.

Ans : Exception handling is bassically used to detect exceptions becouse it can be taken a corresponding action

Ans : EOF bassically stands for End of File, It is used to check for the end of file when a file is being read.

Ans : Parameterized macros are use for the parameters . It is the one which consist of template with insertion points for the addition of parameters.

Ans : Overflow error basically a type of arithmatic errors.It's caused by the result of an arithmetic operation being greater than the actual space provided by the system.

Ans : Nested classes basically useful for organizing code and controlling access and dependencies. Nested classes obey access rules just like other parts of a class do.and that class is a class enclosed within the scope of another class.

Ans : a)It's not pure object oriented programming language.
b)Its a Platform dependent
c)C++ does not give excellant graphics as compare to java.
d)Its Not case sensitive.
e)C++ have Less features as comapred to Java& C#.
f)Its Not applicable in web enviornment.
g)Does not provide very strong type-checking.
h)c++ code is easily prone to errors related to data types, their conversions.
i)Does not provide efficient means for garbage collection.
j)No built in support for threads

Ans : An iterator is a bassically a type of object that represents a stream of data. It is Unlike a sequence, an iterator can only provide the next item. The for-in statement uses iterators to control the loop, and iterators can also be used in many other contexts

Ans : Auto Storage Class is bassically the default. Variables are automatically created and initialized, When they are defined and are destroyed at the end of the block containing their definition. They are not visible outside that block.

Ans : Callback function is the type of pointer for a function

Ans : tellg () provides a information about the current position of input/get pointer.

Ans : tellp ()use for the poitner postion :Its provides the current position of output/put pointer

Ans : Generic Programmng is type of method. The method in which generic types are used as arguments in algorithms for different data types and data structures is called generic programming.

Ans : The Microsoft Foundation Class Library also called as A Microsoft Foundation Classes or MFC. It is basically a library that wraps portions of the Windows API in C++ classes, and including functionality that enables them to use a default application framework. Classes are defined for many of the handle-managed Windows objects and also for predefined windows and common controls. MFC library would help us reduce the code and development time.