Using strcmp and strncmp : strncmp « string.h « C Tutorial

1. C Tutorial
2. string.h
3. strncmp

#include <stdio.h>
#include <string.h>

int main()
{
   const char *s1 = "asdfasdfasdf"; 
   const char *s2 = "fdafdsafdsa"; 
   const char *s3 = "abced"; 
 
   printf("%s%s\n%s%s\n%s%s\n\n%s%2d\n%s%2d\n%s%2d\n\n",
          "s1 = ", s1, "s2 = ", s2, "s3 = ", s3,
          "strcmp(s1, s2) = ", strcmp( s1, s2 ),
          "strcmp(s1, s3) = ", strcmp( s1, s3 ),
          "strcmp(s3, s1) = ", strcmp( s3, s1 ) );

   printf("%s%2d\n%s%2d\n%s%2d\n",
          "strncmp(s1, s3, 6) = ", strncmp( s1, s3, 6 ),
          "strncmp(s1, s3, 7) = ", strncmp( s1, s3, 7 ),
          "strncmp(s3, s1, 7) = ", strncmp( s3, s1, 7 ) );

   return 0; 

}

s1 = asdfasdfasdf
s2 = fdafdsafdsa
s3 = abced

strcmp(s1, s2) = -5
strcmp(s1, s3) = 17
strcmp(s3, s1) = -17

strncmp(s1, s3, 6) = 17
strncmp(s1, s3, 7) = 17
strncmp(s3, s1, 7) = -17