How to Compare Characters in C++?

Last Updated : 06 Feb, 2023

char in c is a keyword used for representing character data type. The memory size of char is 1 byte containing numbers, alphabets, and alphanumeric characters. We can compare the characters in C using 2 different ways:

Comparison using ASCII values.
Using the built-in function.

1. Using ASCII Values

As every character has a unique ASCII value. So, we can use this property for the comparison of characters. Let's see with an example.

// C Program to compare the
// characters using ASCII
// Values
#include <stdio.h>

// Driver code
int main()
{
  // Declaring 2 characters
  char first = 'a';
  char second = 'b';
  char third = 'a';

  // comparing first and 
  // second character
  // equal
  if (first == second) 
      printf("%c and %c are equal\n", 
              first, second);

  else
      printf("%c and %c are not equal\n", 
              first, second);

  // comparing second and 
  // third character
  // equal
  if (first == third) 
      printf("%c and %c are equal\n", 
              first, third);

  else
      printf("%c and %c are not equal\n", 
              first, third);

  return 0;
}

C++

#include <bits/stdc++.h>
using namespace std;

// Driver code
int main()
{
  // Declaring 2 characters
  char first = 'a';
  char second = 'b';
  char third = 'a';

  // comparing first and 
  // second character
  // equal
  if (first == second){
    cout<<first<<" and "<<second<<" are equal \n";
  }

  else{
    cout<<first<<" and "<<second<<" are not equal \n";
  }

  // comparing second and 
  // third character
  // equal
  if (first == third) 
    cout<<first<<" and "<<third<<" are equal \n";

  else
    cout<<first<<" and "<<third<<" are not equal \n";

  return 0;
}

Output

a and b are not equal
a and a are equal

2. Using strcmp Function - (Inbuilt function)

strcmp is a feature provided by <string> library in C. It's a function used to compare strings but can be used to compare characters.

Syntax

strcmp( &ele1 , &ele2 ); // ele1 and ele2 are two elements to be compared

Parameters

ele1 - represent element1 (string).
ele2 - represent element2(string).

Both elements are inserted for comparison.

Return type: strcmp returns an integer value which is according to the result obtained after comparison.

If both are equal returns 0.
else returns -1.

Below is the C program to compare the characters using strcmp:

// C Program to compare the
// characters using strcmp
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// Driver code
int main()
{
  // Declaring 2 characters
  char first[] = "b";
  char second[] = "b";
  char third[] = "a";

  // comparing first and 
  // second character
  if (strcmp(first, second) == 0)
      printf("%s and %s are equal\n", 
              first, second);
  else
      printf("%s and %s are not equal\n", 
              first, second);

  // comparing second and 
  // third character
  if (strcmp(first, third) == 0)
      printf("%s and %s are equal\n", 
              first, third);
  else
      printf("%s and %s are not equal\n", 
              first, third);

  return 0;
}

C++

#include <bits/stdc++.h>
using namespace std;

// Driver code
int main()
{
  // Declaring 2 characters
  char first[] = "b";
  char second[] = "b";
  char third[] = "a";

  // comparing first and 
  // second character
  if (strcmp(first, second) == 0)
      cout<<first<<" and "<<second<<" are equal\n";
  else
      cout<<first<<" and "<<second<<" are not equal\n";

  // comparing second and 
  // third character
  if (strcmp(first, third) == 0)
      cout<<first<<" and "<<third<<" are equal\n";
  else
      cout<<first<<" and "<<third<<" are not equal\n";

  return 0;
}