binary search on array giving wrong index on java

Question

I'm writing a code that does not have to import java Arrays, and that inserts, deletes, and searches a series of values; but the output prints out that it does not find the values on the list when the binSearch() method is called. I have already sorted the array in the main method before calling the binSearch() but it still doesn't find the index of the values.

I'm still a beginner in java, so it would be nice of you if you can explain it to me at a beginner level.

private static int[] insertElement(int index, int array[], int list[], int i) {
    int length = array.length;
    int destination[] = new int[length + 1];
    for (int j = 0; j < destination.length; j++) {
        System.arraycopy(array, 0, destination, 0, index);
        System.arraycopy(array, index, destination, index + 1, length - index);
    }
    destination[index] = list[i];
    System.out.println(list[i] + " is inserted in the list.");
    return destination;
}

private static int[] deleteElement(int index, int[] array, int list[], int i) {
    boolean[] deleteNumber = new boolean[array.length];
    int size = 0;
    for (int j = 0; j < array.length; j++) {
        if (array[j] == list[i]) {
            deleteNumber[j] = true;
            System.out.println(list[i] + " is removed from the list.");
        }
        else {
            deleteNumber[j] = false;
            size++;
        }
    }
    
    int[] newArr = new int[size];
    int in = 0;
    for (int j = 0; j < array.length; j++) {
        if (!deleteNumber[j]) {
            newArr[in++] = array[j];
        }
    }
    return newArr;
}

public static int binSearch(int[] array, int search[], int i) {
    int left = 0;
    int right = array.length - 1;
    
    if (left <= right) {
        int middle = (left + right) / 2;
        if (search[i] < array[middle]) {
            right = middle - 1;
        }
        else if (search[i] > array[middle]) {
            left = middle + 1;
        }
        else {
            System.out.print(search[i] + " is found at location ");
            return middle;
        }
    }
    return -1;
}

 public static void main(String args[]) {
    int arr[] = {2, 4, 6, 8, 9, 10, 20, 33, 44, 45, 68, 88};
    int index = 1;
    
    //insert element
    int newIndex = index - 1;
    int s[] = {3, 78, 98, 12};
    for (int i = 0; i < s.length; i++) {
        arr = insertElement(newIndex, arr, s, i);
    }
    
    //delete element
    int d[] = {20, 44, 89};
    for (int i = 0; i < d.length; i++) {
        arr = deleteElement(newIndex, arr, d, i);
    }
    
    //sort the array
    for (int i = 0; i < arr.length; i++) {
        for (int j = i + 1; j < arr.length; j++) {
            if (arr[i] > arr[j]) {
                int swap = arr[i];
                arr[i] = arr[j];
                arr[j] = swap;
            }
        }
    }
    
    //search for element in array
    BinarySearch ob = new BinarySearch();
    int a[] = {8, 45, 88, 90};
    for (int i = 0; i < a.length; i++) {
        int result = ob.binSearch(arr, a, i);
        if (result == -1) {
            System.out.println(a[i] + " is not found in the list.");
        }
        else {
            System.out.println(result + ".");
        }
    }
    //print array
    printArray(arr);
}

Answer 1

Just replace the if clause with while as you have to search at all levels of the binary search tree. Change

if (left <= right)

to

while (left <= right)

And also there is small issue in your insertElement method.

for (int j = 0; j < destination.length; j++) {
            System.arraycopy(array, 0, destination, 0, index);
            System.arraycopy(array, index, destination, index + 1, length - index);
        }

There is no need of for loop again in the insertElement method as you are already looping through the array that needs to be added in your main method.