Question

Find the sum of squares 1^2 + 2^2 + ... n^2 using iteration and recursion

* I'm guessing we need to modify it

Here's the code unmodified

public class Sum {

//Non recursive sum

public static long sum1 (int n) {

long sum = 1L;

for (int i = 2; i <= n; ++i)

sum = sum + i *i ;

return sum;

}

//Recursive sum

public static long sum2 (int n) {

if (n < 2)return 1L;

return sum2(n - 1) + n * n;

}

}

Answer 1

public class Sum {

    //Non recursive sum
    public static long sum1(int n) {
        long sum = 0L;
        for (int i = 1; i <= n; ++i)
            sum = sum + i * i;
        return sum;
    }

    //Recursive sum
    public static long sum2(int n) {
        if (n < 1) return 0L;
        return sum2(n - 1) + n * n;
    }

    public static void main(String[] args) {
        System.out.println(sum1(10));
        System.out.println(sum2(10));
    }
}