In this tutorial we will learn writing java program to reverse an array without using any other array. This is also known as inplace array reversal program in java.
In previous tutorial we have seen Array reversal in java using second Array.
Inplace Array reversal Program in Java
import java.util.*;
public class Main
{
public static void main(String[] args) {
System.out.println("InPlace Array Reversal Program in Java ");
int startIndex,lastIndex;
Scanner sc = new Scanner(System.in);
System.out.print("Enter the size of array: ");
int size = sc.nextInt();
int arr[] = new int[size];
for(int i=0; i<size; i++) {
System.out.print("Please give value for index "+ i +" : ");
arr[i] = sc.nextInt();
}
startIndex = 0;
lastIndex = size - 1;
while (startIndex < lastIndex)
{
arr[startIndex] = arr[startIndex] + arr[lastIndex];
arr[lastIndex] = arr[startIndex]- arr[lastIndex];
arr[startIndex] = arr[startIndex]- arr[lastIndex];
startIndex++;
lastIndex--;
}
System.out.println("Array After Reversing :");
for(int i=0; i<size; i++)
{
System.out.print(arr[i]+" ");
}
}
}Output
InPlace Array Reversal Program in Java
Enter the size of array: 5
Please give value for index 0 : 6
Please give value for index 1 : 4
Please give value for index 2 : 3
Please give value for index 3 : 6
Please give value for index 4 : 2
Array After Reversing :
2 6 3 4 6 What did you think?