! the logical operator not in C

In this article we will learn about the NOT operator, written as !. This operator reverses the result of the expression it operates on.

For example, if the expression evaluates to a non-zero value, then applying ! operator to it results into a 0. Vice versa, if the expression evaluates to zero then on applying ! operator to it makes it 1, a non-zero value. The final result (after applying !) 0 or 1 is considered to be false or true respectively.


! ( y < 10 )

This means “not y less than 10”. In other words, if y is less than 10, the expression will be false, since ( y < 10 ) is true. We can express the same condition as ( y >= 10 ).

The NOT operator is often used to reverse the logical value of a single variable, as in the expression.

if ( ! flag )

This is another way of saying the same this as below :

if ( flag == 0 )

Does the NOT operator sound confusing? Avoid it if you want, as the same thing can be achieved without using the NOT operator.

not operator
not operator

Satya Prakash

VOIP Expert: More than 8 years of experience in Asterisk Development and Call Center operation Management. Unique Combination of Skill Set as IT, Analytics and operation management.

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