#include <iostream>

double calcTax(double income);

int main()
{
    std::cout << "calcTax(90000.0)   == " << calcTax(90000.0) << "\n";
    std::cout << "calcTax(120000.0)  == " << calcTax(120000.0) << "\n";
    std::cout << "calcTax(750000.0)  == " << calcTax(750000.0) << "\n";
    std::cout << "calcTax(3500000.0) == " << calcTax(3500000.0) << "\n";
    std::cout << "calcTax(9000000.0) == " << calcTax(9000000.0) << "\n";

    return 0;
}

//--------------------------------------------------------------------------
// @description calculate the tax from the income
//              income                  rate
//              <= 100,000                0%
//      100,000 < income <= 500,000      12%
//      500,000 < income <= 1,000,000    15%
//    1,000,000 < income <= 5,000,000    23%
//              > 5,000,000              28%
// @param income the individual income
// @return the tax
// @contract calcTax : double -> double
// @example calcTax(90000.0)   == 0.0
// @example calcTax(120000.0)  == 2400
// @example calcTax(750000.0)  == 85500.0
// @example calcTax(3500000.0) == 698000.0
// @example calcTax(9000000.0) == 2163000.0
//--------------------------------------------------------------------------
double calcTax(double income)
{
    if (income <= 100000.0)
    {
        return 0.0;
    }
    else if (income <= 500000.0)
    {
        return (income - 100000.0) * 0.12;
    }
    else if (income <= 1000000.0)
    {
        return (income - 500000.0) * 0.15 + 48000;
    }
    else if (income <= 5000000.0)
    {
        return (income - 1000000.0) * 0.23 + 123000.0;
    }
    else
    {
        return (income - 5000000.0) * 0.28 + 1043000.0;
    }
}