交换1

#include <iostream>
using namespace std;

void reverse(int a[], int size)
{
    for (int i = 0; i <= (size - 1) / 2; i ++)
    {
       int t = a[i];
       a[i] = a[size - 1 - i];
       a[size - 1 - i] = t;
    }

}

int a[1010];
int main()
{
    int size, n;
    cin >> n >> size;
    for (int i = 0; i < n; i ++) cin >> a[i];
    reverse(a, size);
    for (int i = 0; i < n; i ++) cout << a[i] << ' ';
    return 0;
}

双指针交换

#include <iostream>
using namespace std;

void reverse(int a[], int size)
{
    for (int i = 0, j = size - 1; i < j ; i ++, j --)
        swap(a[i], a[j]);
}

int a[1010];
int main()
{
    int size, n;
    cin >> n >> size;
    for (int i = 0; i < n; i ++) cin >> a[i];
    reverse(a, size);
    for (int i = 0; i < n; i ++) cout << a[i] << ' ';
    return 0;
}