Question

How to reverse an array upto a given index in Java

Answer 1

import java.util.Arrays;

public class MyClass {
    static void reverseUpToIndex(int []arr, int index) {
        if (index > arr.length) {
            System.out.println("Index out of range");
            return;
        }
     
        for (int i = 0; i < index / 2; i++) {
            int temp = arr[i];
            arr[i] = arr[index - i - 1];
            arr[index - i - 1] = temp;            
        }
    }
    public static void main(String args[]) {
        int arr[] = { 1, 4, 8, 0, 7, 3, 9, 5, 6 };
        
        int index = 5;
        
        reverseUpToIndex(arr, index);
 
        System.out.print(Arrays.toString(arr));
    }
}


 
 
/*
run:
 
[7, 0, 8, 4, 1, 3, 9, 5, 6]

*/
 

 

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