Technical Interview Questions and Answers :: Capgemini

Friend Function:
A friend function can access a class private data, even though it is not a member function of the class. This is useful when one function must have access to two or more unrelated classes and when an overloaded operator must use, on its left side, a value of a class other than one of which it is a member. Friends are also used to facilitate functional notation.

Friend Class:
It is possible to grant a non-member function access to the private members of a class by using a friend. A friend function has access to all private and protected members of the class for which it is a friend.

The ++ operator is called the increment operator. When the operator is placed before the variable (++var), the variable is incremented by 1 before it is used in the expression. When the operator is placed after the variable (var++), the expression is evaluated, and then the variable is incremented by 1.

The same holds true for the decrement operator (--). When the operator is placed before the variable, you are said to have a prefix operation. When the operator is placed after the variable, you are said to have a postfix operation.

For instance, consider the following example of postfix incrementation:

int x, y;
x = 1;
y = (x++ * 5);

In this example, postfix incrementation is used, and x is not incremented until after the evaluation of the expression is done. Therefore, y evaluates to 1 times 5, or 5. After the evaluation, x is incremented to 2.

Now look at an example using prefix incrementation:

int x, y;
x = 1;
y = (++x * 5);

This example is the same as the first one, except that this example uses prefix incrementation rather than postfix. Therefore, x is incremented before the expression is evaluated, making it 2. Hence, y evaluates to 2 times 5, or 10.

Physical Level - This is the lowest level of data abstraction which describes which describes how the data is to be stored in the database.

Logical level - The level describes the data in the database as well as relations between these database.

View Level- This is the highest level of data abstraction , only some part of actual database is viewed to the user.