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Q:

To which type of class, We can apply RTTI?

A) Encapsulation B) Polymorphic
C) Derived D) None of these

Answer:   B) Polymorphic



Explanation:

RTTI is available only for classes which are polymorphic, which means they have at least one virtual method.

Subject: C++ - Technology
Q:

What do you mean by friend function in C++ ?

Answer

Friends can be either functions or other classes. The class grants friends unlimited access privileges.

* The declaration of the function should be preceded by the keyword 'friend'.
* The function definition will not use the keyword or the scope operator '::'.


Thus, a friend function is an ordinary function or a member of another class.

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Q:

Give an example for the use of volatile keyword in c++ ?

Answer

Most of the times compilers will do optimization to the code to speed up the program. For example in the below code,


int k = 15;
while( k == 15)


{
// Do something
}


compiler may think that value of 'k' is not getting changed in the program and replace it with 'while(true)', which will result in an infinite loop. In actual scenario, the value of 'k' may be getting updated from outside of the program.


Volatile keyword is used to tell compiler that the variable declared using 'volatile' may be used from outside the current scope, so that compiler won't apply any optimization. This matters only in case of multi-threaded applications.


In the above example if variable 'k' was declared using volatile, compiler will not optimize it. In shot, value of the volatile variables will be read from the memory location directly.

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Q:

Values that are used to end loops are referred to as _____ values.

A) stop B) sentinel
C) end D) finish
 
Answer & Explanation Answer: B) sentinel

Explanation:
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Q:

Which of the following type casts will convert an Integer variable named amount to a Double type ?

A) (int to double) amount B) int (amount) to double
C) int to double(amount) D) (double) amount
 
Answer & Explanation Answer: D) (double) amount

Explanation:
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Q:

What is conversion operator ?

Answer

Class can have a public method for specific data type conversions.
for example:
class B
{
double value;
public  B(int i )
operator double()
{
return value;
}
};
B BObject;
double i = BObject; // assigning object to variable i of type double.
now conversion operator gets called to assign the value.

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Q:

When should we use container classes instead of arrays?

Answer

It is advisable to use container classes of the STL so that you don’t have to go through the pain of writing the entire code for handling collisions, making sure its working well, testing it repeatedly with an overhead of time consumption.


Suppose you have some data that has values associated with strings and its fields consist of grades> in this situation you can directly use hash table instead of having it created by yourself.

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Subject: C++ - Technology

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Q:

What is a container class?

Answer

A class is said to be a container class which is utilized for the purpose of holding objects in memory or persistent media. A generic class plays a role of generic holder. A container class is a good blend of predefined behavior and an interface that is well known. The purpose of container class is to hide the topology for the purpose of objects list maintenance in memory. A container class is known as heterogeneous container, when it contains a set of different objects. A container class is known as homogeneous container when it contains a set of similar objects.

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Subject: C++ - Technology

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Q:

What are static and dynamic type checking?

Answer

Type checking is the operation on which the arguments that can only be applied for.


Static type checking performs the type checking operation before the execution of the program. To perform this operation, the arguments, expressions, variables must be given a data type.


Dynamic type checking performs the type checking operation at the time of the program execution. To perform this operation, the arguments, expressions, variables must be given a data type.

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