In this article, we will discuss how to reverse an array in Java.
So, if we provide an array of [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ] to the program, the output will be an array with elements in reverse order, i.e. [10, 9, 8, 7, 6, 5, 4, 3, 2, 1].
Here is the program :
package com.topjavatutorial;
public class ArrayReverse {
public static void main(String[] args) {
int[] array = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
System.out.println("Original Array : ");
for (int a : array) {
System.out.print(a + " ");
}
int length = array.length;
for(int i = 0; i < length / 2; i++)
{
int temp = array[i];
array[i] = array[length - i - 1];
array[length - i - 1] = temp;
}
System.out.println("\nReversed Array : ");
for (int value : array) {
System.out.print(value + " ");
}
}
}
Output :
Original Array :
1 2 3 4 5 6 7 8 9 10
Reversed Array :
10 9 8 7 6 5 4 3 2 1
We can also convert the array to an ArrayList and use the Collections.reverse() method.
Here is the code :
package com.topjavatutorial;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
public class ArrayReverse {
public static void main(String[] args) {
List<Integer> arrayList = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
System.out.println("Original Array : " + arrayList);
Collections.reverse(arrayList);
System.out.println("\nReversed Array : " + arrayList);
}
}
Output :
Original Array : [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Reversed Array : [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
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