Question

Define a recursive rangeSum(from, to) method that calculates and prints the sum of numbers between the two values inclusive. IN JAVA.

OUTPUT

rangeSum(1,5) -> 15

rangeSum(1,5) -> 1+2+3+4+5=15

rangeSum(-3,4) -> 4

rangeSum(-3,4) -> -3+-2+-1+0+1+2+3+4=4

rangeSum(-5, 7) -> 13

rangeSum(-5, 7) -> -5+-4+-3+-2+-1+0+1+2+3=-9

please write main method as well as output for three above methods.

Answer 1

public class RangeSumTest {

    public static int rangeSum(int from, int to) {
        if (from > to)
            return 0;
        System.out.print(from);
        if (from != to) {
            System.out.print("+");
        } else {
            System.out.print("=");
        }
        return from + rangeSum(from + 1, to);
    }

    public static void main(String[] args) {
        System.out.println(rangeSum(1, 5));
        System.out.println(rangeSum(-3, 4));
        System.out.println(rangeSum(-5, 7));
    }
}