amicable numbers

t04e04.amicable.cpp

// t04e04.amicable.cpp
// juanfc 2024-10-23
// amicable numbers
// 284 220
// 1210 1184
// 2924 2620
// 5564 5020
// 6368 6232
// https://gist.github.com/juanfal/e235970d086c69b1d87db0a37c02c895


#include <iostream>
using namespace std;


int main()
{
    void amicLessThan(int n);
    void printRes(int a, int b);

    printRes(284, 220);
    printRes(121, 212);

    amicLessThan(3000);
    return 0;
}

bool amicable(int a, int b)
{
    int addDivisors(int n);
    return addDivisors(a) == b and
            addDivisors(b) == a;
}

void amicLessThan(int n)
{
    bool amicable(int a, int b);
    int addDivisors(int n);
    for (int i = 1; i <= n; ++i)
        for (int j = 0; j < i; ++j)
            if (amicable(i, j))
                cout << i << " " << j << endl;
}


int addDivisors(int n)
{
    int s = 0;
    for (int i = 1; i < n; ++i)
        if (n % i == 0)
            s += i;
    return s;
}

void printRes(int a, int b)
{
    bool amicable(int a, int b);

    if (amicable(a, b))
        cout << "The numbers " << a << " and " << b << " ARE amicable" << endl;
    else
        cout << "The numbers " << a << " and " << b << " are NOT amicable" << endl;

}