C++ Logical Negation Operator

The logical negation operator ! [exclamation] used in C++ and many other languages. However the return value of the operator is overlooked by many people.

The syntax of the operator follows is

! cast-expression

Where, the cast-expression operand must be of scalar type (returning only a single value, not multiple values like an array)

The result is of type int and is the logical negation of the operand:

 0 if the operand is nonzero

 1 if the operand is zero

To demonstrate the usage of the Logical Negation Operator, the simple program below was written

# include <iostream.h>

# include <conio.h>

 

void main()

{

   clrscr();

 

   cout<<”\nThe expression !0 equals : “<<!0;

   cout<<”\nThe expression !0.7 equals : “<<!0.54;

   cout<<”\nThe expression !4 equals : “<<!4;

   cout<<”\nThe expression !-4 equals : “<<!-4;

 

   getch();

}

 The output of the program is an integer value as expected, the negation of the value 0 (Zero) is equal to 1 and the negation operator applied anything else is equal to 0 (Zero)

 The expression !0 equals : 1

The expression !0.7 equals : 0

The expression !4 equals : 0

The expression !-4 equals : 0

 To summarize, the things to note are that the return type of the operator is int (integer) and the cast-expression operand must be of scalar type

Happy Coding