string are permutations of each other

t11e10.scrabble.cpp

// t11e10.scrabble.cpp
// juanfc 2023-11-22
// https://gist.github.com/d418847eb5c8fece458fe05a5dede7e8

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

typedef array<int,256> TCharFreq;

bool permutations(string a, string b);


void test(string a, string b);
int main()
{
    test("abc", "cba");
    test("abc", "cb");
    test("", "");
    return 0;
}

void test(string a, string b)
{
    cout << '"' << a << "\" and \"" << b << '"';
    if (permutations(a, b))
        cout << " ARE permutations of each other" << endl;
    else
        cout << " are NOT permutations of each other" << endl;
}


TCharFreq getFreqs(string s);
bool permutations(string a, string b)
{
    if (a.length() == b.length()) {
        TCharFreq af = getFreqs(a);
        TCharFreq bf = getFreqs(b);
        return af == bf;
    } else
        return false;
}

TCharFreq getFreqs(string s)
{
    TCharFreq r;
    for (int i = 0; i < 256; ++i)
        r[i] = 0;

    for (int i = 0; i < s.length(); ++i)
        ++r[s[i]];
    return r;
}