배열을 역순으로 정렬하기

import java.util.Scanner;
import java.util.Arrays;

public class ReverseArray {
  
  static void swap(int[] a, int idx1, int idx2) {
    // 실제로 위치를 교체
    int t = a[idx1];
    a[idx1] = a[idx2];
    a[idx2] = t;
  }
  
  static void reverse(int[] a) {
    
    for(int i=0; i<a.length / 2; i++){
      //위치를 교체할 element의 인덱스를 반복해서 입력
      swap(a, i, a.length-1-i);
    }
  }
  
  
  
    public static void main(String[] args) {
      Scanner sc = new Scanner(System.in);
      System.out.print("input array size: ");
      int elmntNum = sc.nextInt();
      
      int[] a = new int[elmntNum];
      
      for(int i=0; i < a.length; i++) {
        System.out.print("input elements: ");
        int num = sc.nextInt();
        a[i] = num;
      }
      //입력받은 배열을 대입
      reverse(a);
      
      //역순 출력
      System.out.println(Arrays.toString(a));
      
    }
}



/*
input array size: 10
input elements: 1
input elements: 2
input elements: 3
input elements: 4
input elements: 5
input elements: 6
input elements: 7
input elements: 8
input elements: 9
input elements: 10
[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
*/