#include <stdio.h>
int main(void) {
    int a[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    int k;
    for (int i = 0; i < 5; i++) {
        k = *(a+i);
        *(a + i) = *(a + (9 - i));
        *(a + (9 - i)) = k;
    }
    for (int i = 0; i < 10; i++)
        printf("%d ", *(a+i));
    return 0;
}