strcmp : <string.h> library function

The function int strcmp(const char *str1, const char *str2); compares string pointed by str1 with string pointed by str2. This function compares both string character by character. It will continue comparison until the characters mismatch or until a terminating null-character is reached.

Function prototype of strcmp

int strcmp(const char *str1, const char *str2);
  • str1 : A pointer to a C string to be compared.
  • str2 : A pointer to a C string to be compared.

Return value of strcmp

Return Value Description
Positive (>0) str2 is less than str1
Zero (==0) str1 is equal to str2
Negative (<0) str1 is less than str2

C program to show the use of strcmp function

The following program shows the use of strcmp function to compare two strings.

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

int main()
{
   char firstString[100], secondString[100];
   int response;
   printf("Enter first string\n");
   scanf("%s", &firstString);
   printf("Enter second string\n");
   scanf("%s", &secondString);
   
   response = strcmp(firstString, secondString, 5);

   if(response > 0){
      printf("second String is less than first String");
   } 
   else if(response < 0) {
      printf("first String is less than second String");
   }
   else {
      printf("first String is equal to second String");
   }
   
   getch();
   return(0);
}

Program Output
Enter first string
asdfg
Enter second string
ASDFG
second String is less than first String
Enter first string
testString
Enter second string
testString
first String is equal to second String