Find if two strings are anagrams

Write a program to find if two strings are anagrams

Anagram - Wikipedia

An anagram is a type of word play, the result of rearranging the letters of a word or phrase to produce a new word or phrase, using all the original letters exactly once; for example orchestra can be rearranged into carthorse.

The approach:-

• Check string lengths.
• Initialize a frequency table to keep count of characters seen.
• Scan the first string and increment the frequency table.
• Scan the second string and decrement the frequency table.
• Check if the frequency table has count more than zero in any of the locations. If so, not an anagram. Else, anagram.

C++ program to find if two strings are anagrams

#include <iostream>
#include <cstring>

using namespace std;

#define MAX_ASCII 127

int main()
{
    char s1[] = "orchestra";
    char s2[] = "carthorse";

    if ( strlen(s1) != strlen(s2) )
    {
        cout << "Not anagram" << endl;
        return 0;
    }

    int freq[MAX_ASCII + 1];

    for ( int i = 0; i < MAX_ASCII + 1; i++ )
        freq[i] = 0;

    char* ptr1 = s1;
    while ( *ptr1 != '\0' ) {
        char c = tolower(*ptr1);
        freq[(int)c]++;
        ptr1++;
    }

    char *ptr2 = s2;
    while ( *ptr2 != '\0' ) {
        char c = (char)tolower(*ptr2);
        freq[(int)c]--;
        ptr2++;
    }

    for ( int i = 0; i < MAX_ASCII + 1; i++ )
        if ( freq[i] > 0 )
        {
            cout << "Not anagram" << endl;
            return 0;
        }
        else
        {
            continue;
        }

    cout << "Anagram" << endl;
    return 0;
}

Output:-

Anagram