/**

• Determines if 2 strings are anagrams of each other, meaning that they both contain all of the same letters
• Returns 1 if the strings are anagrams, 0 otherwise
• Note: The function only checks lower case letters from 'a' to 'z'. No other characters will be given as input
• Example: "test" and "etts" should return 1, "car" and "cat" should return 0
• @param char * str1 (only contains lower case characters)
• @param char * str2 (only contains lower case characters)
• @return 1 if two strings are anagrams, 0 if they are not
  */

int checkAnagram(char* str1, char* str2) {
    //check to see if both strings are NULL
    if(str1 == NULL && str2 == NULL){
        return 1;
    }
    
    //find lengths of both strings
    int len1 = mystrlen(str1);
    int len2 = mystrlen(str2);

    if(len1 != len2){
        return 0;
    }
    
    //initialize array of size 26 to represent the letters of the alphabet and set all values to 0
    //Eg: alphabet[0] corresponds to 'a' , alphabet[1] corresponds to 'b'
    int alphabet[26]={0};

    //change values in alphabet array as they appear in the input strings
    int i = 0;
    for(i = 0; i < len1; i++){
        alphabet[str1[i] - 'a']++;
        alphabet[str2[i] - 'a']--;  //should be --
    }

    //check to see if all elements in the array are still 0
    for(i = 0; i < 26; i++){
        if(alphabet[i] !=  0){ 
            return 0;        
        }
    }
    return 1;
}