Finding the index of the smallest element in an array (Java)

Question

I am trying to write up a block of code that takes an array of integers as an argument and returns the index of the smallest element in the array. Also, the function should return -1 if the list is an empty list.

So far I have got,

public static int indexOfSmallest(int[] array){
    int index = 0;
    int min = array[index];

    for (int i = 1; i < array.length; i++){
        if (array[i] <= min){
        min = array[i];
        index = i;
        }
    }
        return index;
}

But, I'm getting this error and unsure what I need to fix.

Any help would be much appreciated. Thank you.

Answer 1

The error is self explanatory. You fail to handle the case of empty input array.

public static int indexOfSmallest(int[] array){

    // add this
    if (array.length == 0)
        return -1;

    int index = 0;
    int min = array[index];

    for (int i = 1; i < array.length; i++){
        if (array[i] <= min){
        min = array[i];
        index = i;
        }
    }
    return index;
}

If the smallest element appears multiple times, and you want to return the index of its first occurrence, change your condition to:

if (array[i] < min)