strcmp
Syntax:
  #include <string.h>
  int strcmp( const char *str1, const char *str2 );

The function strcmp() compares str1 and str2, then returns:

Return value Explanation
less than 0 ''str1'' is less than ''str2''
equal to 0 ''str1'' is equal to ''str2''
greater than 0 ''str1'' is greater than ''str2''

For example:

   printf( "Enter your name: " );
   scanf( "%s", name );
   if( strcmp( name, "Mary" ) == 0 )
     printf( "Hello, Dr. Mary!\n" );          

Note that strcmp() does not perform bounds checking, and thus risks overrunning str1 or str2. For a similar (and safer) function that includes bounds checking, see strncmp().