!=                       Inequality operator (Not Equal)
 
 exp1 != exp2            Test for exp1 not equal to exp2
 exp1, exp2              any expression of type int, float, char, enum,
                         or related type
 
    != is a relational operator, yielding a value of 1 (TRUE) if exp1 has
    a different value than exp2; or 0 (FALSE) if exp1 has the same value
    as exp2.  Type conversion is performed as necessary before comparing
    the expressions, using the usual arithmetic conversions.  Example:
 
           if (number != guess)
               ...
           do  {
               ...
           } while (ans != 'n');

Seealso:


 Conversions 
 ==