C library function - strncmp()

Description

The C library function int strncmp(const char *str1, const char *str2, size_t n) compares at most the first n bytes of str1 and str2.

Declaration

Following is the declaration for strncmp() function.

int strncmp(const char *str1, const char *str2, size_t n)

Parameters

• str1 − This is the first string to be compared.

• str2 − This is the second string to be compared.

• n − The maximum number of characters to be compared.

Return Value

This function return values that are as follows −

• if Return value < 0 then it indicates str1 is less than str2.

• if Return value > 0 then it indicates str2 is less than str1.

• if Return value = 0 then it indicates str1 is equal to str2.

Example

The following example shows the usage of strncmp() function.

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

int main () {
   char str1[15];
   char str2[15];
   int ret;

   strcpy(str1, "abcdef");
   strcpy(str2, "ABCDEF");

   ret = strncmp(str1, str2, 4);

   if(ret < 0) {
      printf("str1 is less than str2");
   } else if(ret > 0) {
      printf("str2 is less than str1");
   } else {
      printf("str1 is equal to str2");
   }
   
   return(0);
}

Let us compile and run the above program that will produce the following result −

str2 is less than str1