    #include <iostream>
    #include <string>

    using namespace std;

    int main()
    {
       const double SINGLE_LEVEL1 = 21450.00;
       const double SINGLE_LEVEL2 = 51900.00;

       const double SINGLE_TAX1 = 3217.50;
       const double SINGLE_TAX2 = 11743.50;

       const double MARRIED_LEVEL1 = 35800.00;
       const double MARRIED_LEVEL2 = 86500.00;

       const double MARRIED_TAX1 = 5370.00;
       const double MARRIED_TAX2 = 19566.00;

       const double RATE1 = 0.15;
       const double RATE2 = 0.28;
       const double RATE3 = 0.31;

       double income;
       double tax;

       cout << "Please enter your income: ";
       cin >> income;

       cout << "Please enter s for single, m for married: ";
       string marital_status;
       cin >> marital_status;

       if (marital_status == "s")
       {
          if (income <= SINGLE_LEVEL1)
             tax =  RATE1 * income;
          else if (income <= SINGLE_LEVEL2)
             tax = SINGLE_TAX1
                + RATE2 * (income - SINGLE_LEVEL1);
          else
             tax = SINGLE_TAX2
                + RATE3 * (income - SINGLE_LEVEL2);
       }
       else
       {
          if (income <= MARRIED_LEVEL1)
             tax =  RATE1 * income;
          else if (income <= MARRIED_LEVEL2)
             tax = MARRIED_TAX1
                + RATE2 * (income - MARRIED_LEVEL1);
          else
             tax = MARRIED_TAX2
                + RATE3 * (income - MARRIED_LEVEL2);
       }
       cout << "The tax is $" << tax << "\n";
       return 0;
    }