Question

HELLO.

I'M KINDA NEW TO JAVA AND I NEED HELP WITH A METHOD. USING RECURSION ONLY.

public static int sumaEnRango (int start,int end)

-RECURSIVE METHOD THAT RETURNS THE SUM OF ALL THE CONSECUTIVE INTEGER NUMBERS BETWEEN "START" AND "END. IT ALSO RETURNS 0 IN CASE "START" IS GREATER THAN "END" 

THIS METHOD RETURNS AN ARITHMERIC EXCEPTION IN CASE THE PARAMETER NUMBER IS NEGATIVE

I KNOW THIS IS SIMPLE METHOD BUT I'M STILL CONFUSED WHEN USING RECURSION.

THANKS A LOT !!!

Answer 1

public class RecursiveSumRange {

    public static int sumaEnRango(int start, int end) {
        if (start < 0 || end < 0)
            throw new ArithmeticException();
        if (start > end)
            return 0;
        return start + sumaEnRango(start+1, end);
    }

    public static void main(String[] args) {
        System.out.println(sumaEnRango(1, 10));
        System.out.println(sumaEnRango(5, 10));
        System.out.println(sumaEnRango(10, 5));
        try {
            System.out.println(sumaEnRango(-1, 5));
        } catch (ArithmeticException e) {
            System.out.println("Invalid. negative parameters were given");
        }
    }
}