private Dollars Charge(int usage)
{
Dollars result;
if (usage == 0) return new Dollars(0);
double t1 = START_RATE - ((END_RATE*END_AMOUNT) - START_RATE)/(END_AMOUNT - 1);
double t2 = ((END_RATE*END_AMOUNT) - START_RATE)*Math.Min(END_AMOUNT, usage)/
(END_AMOUNT - 1);
double t3 = Math.Max(usage - END_AMOUNT, 0)*END_RATE;
result = new Dollars(t1 + t2 + t3);
result = result.Plus(new Dollars(usage*0.0175));
Dollars base1 = new Dollars(result.Min(new Dollars(50)).Times(0.07));
if (result.IsGreaterThan(new Dollars(50)))
{
base1 = new Dollars(base1.Plus(result.Min(new Dollars(75)).Minus(
new Dollars(50)).Times(0.06)
));
}
if (result.IsGreaterThan(new Dollars(75)))
{
base1 = new Dollars(base1.Plus(result.Minus(new Dollars(75)).Times(0.05)));
}
result = result.Plus(base1);
return result;
}
private Dollars Charge(int usage)
{
double base1 = Math.Min(usage, 100)*0.03;
if (usage > 100)
{
base1 += (Math.Min(usage, 200) - 100)*0.05;
}
if (usage > 200)
{
base1 += (usage - 200)*0.07;
}
Dollars result = new Dollars(base1);
Dollars tax = new Dollars(result.Minus(new Dollars(8)).Max(new Dollars(0)).Times(TAX_RATE));
result = result.Plus(tax);
Dollars fuelCharge = new Dollars(usage*0.0175);
result = result.Plus(fuelCharge);
return result.Plus(new Dollars(fuelCharge.Times(TAX_RATE)));
}