memcmp c – memcmp C Library Function

memcmp c: The function int memcmp(const void *ptr1, const void *ptr2, size_t n); compares first n bytes starting from memory location pointed by ptr1 with first n bytes starting from memory location pointed by ptr2.

Function prototype of memcmp

int memcmp(const void *ptr1, const void *ptr2, size_t n);

• ptr1 : A pointer to the block of memory.
• ptr2 : A pointer to the block of memory.
• n : This is the number of bytes to compare.

Return value of memcmp

C program using memcmp function

C memcmp: The following program shows the use of memcmp function to compare two strings.

#include <stdio.h>
#include <string.h>
#include <conio.h>
 
int main()
{
   char firstString[100], secondString[100];
   int length, response;
   printf("Enter length of strings\n");
   scanf("%d", &length);
   printf("Enter first string of length %d\n", length);
   scanf("%s", &firstString);
   printf("Enter second string of length %d\n", length);
   scanf("%s", &secondString);
    
   response = memcmp(firstString, secondString, length);
 
   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);
}

Output

Enter length of strings
7
Enter first string of length 7
ASDFGHJ
Enter second string of length 7
QWERTYU
first String is less than second String