The **`strcmp()` function** is a built-in library function declared in the *string.h* header file. It *compares* two strings and returns an integer after comparison.

# Syntax

`strcmp()` takes two strings as arguments and returns an integer. Strings are case sensitive, i.e., abc is *not* equal to Abc.

# Cases

Every character holds an [ASCII](http://www.asciitable.com) value (an integer ranging from `0` to `127`), for example, *A* holds the ASCII value of `65` and *a* holds the ASCII value of `97`. So, in the comparison between two strings, their ASCII values are compared. Let's look at the possible cases:

## Case 1
If `Str1` is equal to `Str2`, it returns a $0$:


## Case 2
If `Str1` is less than `Str2`, it returns a $-32$ (negative value):

## Case 3
If `Str1` is greater than `Str2`, it returns a $32$ (positive value):

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

int main() {
  char str1[] = "abcd", str2[] = "abcd";
  int a = strcmp(str1, str2);
  printf("Case 1: %d\n\n", a);
  
  char Str1[] = "abCd", Str2[] = "abcd";
  a = strcmp(Str1, Str2);
  printf("Case 2: %d\n\n", a);
  
  char STR1[] = "abcd", STR2[] = "abCd";
  a = strcmp(STR1, STR2);
  printf("Case 3: %d\n\n", a);
  return 0;
}

How to compare strings using strcmp() function in C

The strcmp() function is a built-in library function declared in the string.h header file. It compares two strings and returns an integer after comparison. Syntax strcmp() takes two strings as arguments and returns an integer. Strings are case sensitive, i.e., abc is not equal to Abc. 