Max.java

public class Max {
    public static void main(String[] args) {

        int [] arr = {1, 3, 23, 9, 18};
        System.out.println(maxRange(arr, 1,3));

    }
    // work on edge cases here, lik array being null
    static int maxRange(int[]arr, int start, int end){
        if(end>start){
            return -1;
        }
        if (arr==null){
            return -1;
        }
        int maxVal = arr[start];
        for (int i = 1; i<=end;i++){
            if(arr[i]>maxVal){
                maxVal=arr[i];
            }
        }
        return maxVal;
    }
    // imagine that arr is not empty
    static int max(int[]arr){
        if (arr.length==0){
            return -1;
        }
        int maxVal = arr[0];
        for (int i = 1; i<=arr.length;i++){
            if(arr[i]>maxVal){
                maxVal=arr[i];
            }
        }
        return maxVal;
    }
}