Converting iterative code to recursive code

Question

I need some help with that function. I gonna use "val" in other functions but when I try to return the value in a recursive function just return 0. I need to make this loop in a recursive function Sorry for my English. Thanks a lot

int val = 0;
for (int i = 0; i < arreglo.length; i++) {
    if (arreglo[i] % 2 != 0) {
        val++;
    }
}

Answer 1

Here's a simple example how this can be done:

For the base case of recursion you have to provide starting index and initial value, so pass 0 for index parameter and 0 for val parameter:

public class Recursive{
     public static int recursive(int[] arreglo, int index, int val) {
         if (index == arreglo.length ) {
             return val;
         } else {
             if (arreglo[index] % 2 == 0) {
                 val++;  // increment value - even number
             }
             return recursive(arreglo, index+1, val);
         }
     }
 
     public static void main(String []args){
         int[] r = {1, 2, 3, 4, 5, 6, 7, 8};
         int result = recursive(r, 0, 0);
         System.out.println(result); // Outputs 4 
     }
}