Main for Sale calculator

Example.java

package Java_FP.FP;

/**
 * Created by liuyufei on 18/10/16.
 */
public class Example {

    final static double[] EXPECTED_SALES_JAN_TO_DEC =
            new double[]{42.0, 45.6, 43.6, 50.2, 55.6, 54.7,
                    58.0, 57.3, 62.0, 60.3, 71.2, 88.8
            };


    public static void main(String[] args) {

        final FunctionOverTime sales =
                FunctionOverTime.monthByMonth(EXPECTED_SALES_JAN_TO_DEC);

        final FunctionOverTime fixedCost = FunctionOverTime.constant(15.0);
        final FunctionOverTime incrementalCosts = FunctionOverTime.line(5.1,0.15);

        //high order function!!!
        final FunctionOverTime profit =
                FunctionOverTime.combinationOf3(
                        sales,incrementalCosts,fixedCost,
                        (s,ic,fc) -> s-ic-fc
                );

        double total = 0.0;
        for (int i = 1; i <= 12; i++) {
            total += profit.valueAt(i);
        }

        System.out.println("Total profits for the year: " + total);
    }
}