//Program to compute state income tax.
#include <iostream.h>

double tax(int net_income);
//Precondition: The formal parameter net_income is net income, rounded
//to a whole number of dollars.
//Returns the amount of state income tax due computed as follows:
//no tax on income up to $15,000; 5% on income between $15,001
//and $25,000 plus 10% on income over $25,000.

int main( )
{
    int net_income;
    double tax_bill;

    cout << "Enter net income (rounded to whole dollars) $";
    cin >> net_income;

    tax_bill = tax(net_income);

    cout.setf(ios::fixed);
    cout.setf(ios::showpoint);
    cout.precision(2);
    cout << "Net income = $" << net_income << endl
         << "Tax bill = $" << tax_bill << endl;

    return 0;
}

double tax(int net_income)
{
    double five_percent_tax, ten_percent_tax;

    if (net_income <= 15000)
        return 0;
    else if ((net_income > 15000) && (net_income <= 25000))
        //return 5% of amount over $15,000
        return (0.05*(net_income - 15000));
    else //net_income > $25,000
    {
        //five_percent_tax = 5% of income from $15,000 to $25,000.
        five_percent_tax = 0.05*10000;
        //ten_percent_tax = 10% of income over $25,000.
        ten_percent_tax = 0.10*(net_income - 25000);
        return (five_percent_tax + ten_percent_tax);
    }
}