What is sizeof() ?

The sizeof() operator is a special type of operator which is used to show the memory space occupied by the data types or operands in bytes.
In other word, it returns number of bytes occupied by the operand. It is used within an operand. It is a return type function which returns a value.

  Ex:

     x = sizeof (char);

     y = sizeof (int);

The value of x is 1 and the value of y is 2 because char (character) data type occupied 1 byte memory space and the int (integer) data type occupied 2 byte memory space.