31. What do you mean by virtual methods?
Ans: virtual methods are used to use the polymorphism feature in C++. Say class A is inherited from class B. If we declare say function f() as virtual in class B and override the same function in class A then at runtime appropriate method of the class will be called depending upon the type of the object.
32. How many ways are there to initialize an int with a constant?
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);
33. What is destructor?
Ans: Destructor is a special member function of a class, which is invoked automatically whenever an object goes out of the scope. It has the same name as its class with a tilde character prefixed.
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Ans: virtual methods are used to use the polymorphism feature in C++. Say class A is inherited from class B. If we declare say function f() as virtual in class B and override the same function in class A then at runtime appropriate method of the class will be called depending upon the type of the object.
32. How many ways are there to initialize an int with a constant?
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);
33. What is destructor?
Ans: Destructor is a special member function of a class, which is invoked automatically whenever an object goes out of the scope. It has the same name as its class with a tilde character prefixed.
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34. What is an explicit constructor?
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.
35. What is the Standard Template Library?
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.
36. What is the use of ‘using’ declaration?
Ans: A using declaration makes it possible to use a name from a namespace
37. What problem does the namespace feature solve?
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.
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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.
35. What is the Standard Template Library?
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.
36. What is the use of ‘using’ declaration?
Ans: A using declaration makes it possible to use a name from a namespace
37. What problem does the namespace feature solve?
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.
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38. What do you mean by Stack unwinding?
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.
39. What is a template?
Ans: Templates allow us to create generic functions that admit any data type as parameters and return a 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 function_declaration;
template function_declaration;
40. What is the difference between a copy constructor and an overloaded assignment operator?
Ans: 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.
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.
39. What is a template?
Ans: Templates allow us to create generic functions that admit any data type as parameters and return a 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 function_declaration;
template function_declaration;
40. What is the difference between a copy constructor and an overloaded assignment operator?
Ans: 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.
