Question

I was studying recursion problem
I was going to call it, but it shows like this

import java.util.Arrays;


public class BinarySearch {
public static int binarySearch(int [] list, int key){
    int low = 0;
    int high = list.length -1;
    return binarySearch(list, key, low ,high);
}
public static int binarySearch(int [] list, int key, int low, int high){
    if(low > high){
        return (-low -1);}
    int mid = (low + high) / 2;
    if(key < list[mid])
        return binarySearch(list, key, low, mid - 1);
    else if(key == list[mid])
        return mid;
    else
        return binarySearch(list, key, mid + 1, high);
}
public static void main (String [] args){
    int [] list = {'1', '2','4','5'};
    binarySearch(list, 4);
    System.out.println(Arrays.toString(list));

}

}

output : [49, 50, 52, 53]

what should I do to make it correct?

Answer 1

You are storing characters in integer array: –

int [] list = {'1', '2','4','5'};

So, the values you obtained is the ASCII code for 1, 2, 4, 5 respectively. Due to this, your binarySearch method would not be able to find the value 4 ever. As, it is not exactly there. Remove those single quotes around your values.

Secondly, you are not printing the return value of binarySearch method: –

binarySearch(list, 4);

should be: –

System.out.println(binarySearch(list, 4));