C++ cstring strcmp() Function

The C++ cstring strcmp() Function compares two strings and returns the difference between them.

This function is similar to the memcmp() function, but the memcmp() function returns the difference between memory buffers, whereas, this function returns the difference between the two strings.

This function is useful when we don't have to write complex conditional statements to compare two strings. This function is case-sensitive, means "Hello" and "hello" are not equal.

Syntax

Following is the syntax of the C++ cstring strcmp() function −

int strcmp(const char *str1, const char *str2);

Parameters

Following are the parameters of this function −

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

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

Return Values

This function returns −

• 0: If both strings are equal.
• 1: If the first character that does not match has a lower value in str1 than in str2.
• -1: If the first character that does not match has a greater value in str1 than in str2.

Example 1

Following is an example to show the usage of strcmp() function.

In this, we will compare two strings str1 and str2 using strcmp() function.

#include <iostream>
#include <cstring>
using namespace std;

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

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

   ret = strcmp(str1, str2);

   if(ret > 0) {
      cout << "str1 is greater than str2"<<endl;
   } else if(ret < 0) {
      cout << "str1 is less than str2"<<endl;
   } else {
      cout << "str1 is equal to str2"<<endl;
   }

   return 0;
}

Output

Following is the output of the above C++ program:

str1 is less than str2

Example 2

Now, Let's take two strings str1 and str2, both will be the same but one will be in uppercase and another in lowercase. We then compare these two strings using strcmp() function.

#include <iostream>
#include <cstring>

using namespace std;

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

   strcpy(str1, "Hello");
   strcpy(str2, "hello");

   ret = strcmp(str1, str2);

   if(ret > 0) {
      cout << "str1 is greater than str2"<<endl;
   } else if(ret < 0) {
      cout << "str1 is less than str2"<<endl;
   } else {
      cout << "str1 is equal to str2"<<endl;
   }

   return 0;
}

Output

Following is the output of the above C++ program −

str1 is less than str2