C Program to Check Whether Two Strings Are Anagrams

Program

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

int checkAnagram(char *str1, char *str2);

int main()
{
    char str1[100], str2[100];
    
    printf("Function : whether two given strings are anagram :");
    printf("\nExample : pears and  spare, stone and tones :");
    
    printf(" Input the  first String : ");
    fgets(str1, sizeof str1, stdin);
    printf(" Input the  second String : ");
    fgets(str2, sizeof str2, stdin);
 
    if(checkAnagram(str1, str2) == 1)
    {
       str1[strlen(str1)-1] = '\0';
       str2[strlen(str2)-1] = '\0';
       printf(" %s and %s are Anagram.\n\n",str1,str2);
    } 
    else 
    {
       str1[strlen(str1)-1] = '\0';
       str2[strlen(str2)-1] = '\0';
       printf(" %s and %s are not Anagram.\n\n",str1,str2);
    }
    return 0;
}
 
    
//Function to check whether two passed strings are anagram or not

int checkAnagram(char *str1, char *str2)
{
    int str1ChrCtr[256] = {0}, str2ChrCtr[256] = {0};
    int ctr;
    
    /* check the length of equality of Two Strings */
    
    if(strlen(str1) != strlen(str2))
    {
        return 0;
    }
    
    //count frequency of characters in str1 
    
    for(ctr = 0; str1[ctr] != '\0'; ctr++)
    {
        str1ChrCtr[str1[ctr]]++;
    }
    
    //count frequency of characters in str2 
    
    for(ctr = 0; str2[ctr] != '\0'; ctr++)
    {
        str2ChrCtr[str2[ctr]]++;
    }
    
    //compare character counts of both strings 
    
    for(ctr = 0; ctr < 256; ctr++)
    {
        if(str1ChrCtr[ctr] != str2ChrCtr[ctr])
            return 0;
    }
    return 1;
}

Output

Function : whether two given strings are anagram :
Example : pears and spare, stone and tones :
Input the  first String : pears
Input the  second String : spare
pears and spare are Anagram.