请问这个程序填空题怎么做？

/* 程序段A */
# define MAXN 10
int i, high, low, n, temp;
int num[MAXN];

scanf("%d", &n);
for(i = 0; i < n; i++){
    scanf("%d", &num[i]);
}
_____________________

while(______________________)
{
    temp = num[high];
    num[high] = num[low];
    num[low] = temp;
    _____________________

}
for(i = 0; i < n; i++) {
    printf("%d ", num[i]);
}
printf("\n");

/* 程序段B */
# define MAXN 10
int i, n, temp;
int num[MAXN];
scanf("%d", &n);
for(i = 0; i < n; i++)
    scanf("%d", &num[i]);
for_____________________
 {
    _____________________
}
for(i = 0; i < n; i++) {
    printf("%d ", num[i]);
}
printf("\n");