makeChange

#include<iostream>
#include<string>

using namespace std;

int makeChange(float total, float paid)
{
    float denom[] = {.01, .05, .10, .25, 1, 5, 10, 20};
    string denomStr[2][8] = {
        { "penny", "nickel", "dime", "quarter", "single", "five", "ten", "twenty" },
        { "pennies", "nickels", "dimes", "quarters", "singles", "fives", "tens", "twenties" },
    };
    float change = paid - total;

    cout.precision(2);

    if (change < 0)
    {
        cout << "You don't have enough to purchase this item." << endl;
        return -1;
    }
    else if (change == 0)
    {
        cout << "No change given." << endl;
        return 0;
    }
    else
        cout << fixed << total << " from " << paid << " returns:" << endl;

    // main algorithm:
    int d, i = 7;
    while (i >= 0)
    {
        if (change >= denom[i])
        {
            d = 0;
            while (change >= denom[i])
            {
                change = change - denom[i];
                d++;
            }
            if (d == 1)
                cout << d << " x " << denomStr[0][i] << endl;
            else
                cout << d << " x " << denomStr[1][i] << endl; //plurals
        }
        i--;
    }
    return 0;
}

int main()
{
    makeChange(3.21, 5.00);
    makeChange(5.00, 3.21);
    makeChange(19.74, 20.00);

    return 0;
}