Question

I need help with a concept that will be on my Java exam. I need to write a method that takes an array and returns a new array with each element being the sum of the elements before it. i.e the first array is {3, 2, 1, 4} and the array the method returns is {3, 5, 6, 10}

Here is my code so far:

public class testPrac1 {
public static void main(String[] args){
    int[] array = {3, 2, 1, 4};

    for (int value: sum(array)) {
        System.out.print(value);
    }
}
public static int[] sum(int[] array) {
    int[] newArray = new int[array.length];

    for (int i = 0; i < array.length ; i++) {
        if (i == 0){
            newArray[i] = array[0];
        }
        else 
            for (int j = 0; j < i; j++) 
                    newArray[i]  =  (array[i] + array[j]);
    }

    return newArray;
}

}

Answer 1

And just to spice it up, how about:

public static int[] sum(int[] array) {
  int[] newArray = new int[array.length];

  for (int i = 0; i < array.length; i++) {
    newArray[i] = array[i];
    if (i > 0) {
      newArray[i] += newArray[i-1];
    }
  }

  return newArray;
}