二级 · 程序填空：二分查找的边界

下面程序在有序数组中二分查找 35，输出它的下标 6。请在【】处填入正确的内容。

#include <stdio.h>

int main(void)
{
    int a[10] = {2, 7, 11, 18, 24, 29, 35, 40, 51, 63};
    int x = 35, low = 0, high = 9, mid, pos = -1;
    while (low 【0】 high)
    {
        mid = 【1】;
        if (a[mid] == x)
        {
            pos = mid;
            break;
        }
        else if (a[mid] < x)
            low = 【2】;
        else
            high = mid - 1;
    }
    printf("%d\n", pos);
    return 0;
}