Write a java program fills in an array with up to 20 nonnegative whole numbers a

Question

Write a java program fills in an array with up to 20 nonnegative whole numbers and the searches the array for values specifid by the user.

I would like to see that you are using binary searsh:

- Implemented by while loop

-implemened by recursion

in the same main

by using this code for while loop:

static int BinarySearch(char target, char array[]) {
    int low=0, high = 19, middle;
    while( low<=high) {
        middle = (low+high)/2;
        if( array[middle]==target )
            return middle;
        else if( array[middle]<target )
            low = middle + 1;
        else
            high = middle - 1;
    }
    return -1;
}

and this code for recursion:

static int BinarySearch(char target, int low, int high, char[] array) {

       if( target<array[low] || target>array[high] )

           return -1;

       int middle = (low+high)/2;

       if( array[middle]==target )

           return middle;

       else if( array[middle]>target )

   return BinarySearch(target, low, middle-1, array);

   else

   return BinarySearch(target, middle+1, high, array);

}

Explanation / Answer

Here is the code for you:

import java.util.*;
class BinarySearchVersions
{
    public static int BinarySearchIterative(int target, int array[])
    {
       int low=0, high = 19, middle;
       while( low<=high)
       {
          middle = (low+high)/2;
          if( array[middle]==target )
              return middle;
          else if( array[middle]<target )
              low = middle + 1;
          else
              high = middle - 1;
       }
       return -1;
    }
    public static int BinarySearchRecursive(int target, int low, int high, int[] array)
    {
if( target<array[low] || target>array[high] )
return -1;
int middle = (low+high)/2;
if( array[middle]==target )
return middle;
else if( array[middle]>target )
return BinarySearchRecursive(target, low, middle-1, array);
else
return BinarySearchRecursive(target, middle+1, high, array);
}
    public static void main(String[] args)
    {
       //fills in an array with up to 20 nonnegative whole numbers
       int[] array = new int[20];
       System.out.print("Enter 20 non-negative values: ");
       Scanner sc = new Scanner(System.in);
       for(int i = 0; i < 20; i++)
       {
          array[i] = sc.nextInt();
          if(array[i] < 0)
          {
             System.out.print("Negative values are not allowed. Please re-enter: ");
             i--;
          }
       }
       System.out.print("Enter a search key to search from: ");
       int key = sc.nextInt();
       int pos = BinarySearchIterative(key, array);
       if(pos == -1)
           System.out.println("Element not found in the list.");
       else
           System.out.println("Element found at index: " + pos);
      
       pos = BinarySearchRecursive(key, 0, 19, array);
       if(pos == -1)
           System.out.println("Element not found in the list.");
       else
           System.out.println("Element found at index: " + pos);      
          
         
    }
}

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