int main(void) {
    int arr[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};//有序的数组
    int sz = sizeof(arr) / sizeof(arr[0]);
    int lIndex = 0;
    int rIndex = sz - 1;
    int kit = 7; //查找数
    while (lIndex <= rIndex) {
        int mid = (lIndex + rIndex) / 2;
        if (kit > arr[mid]) {
            lIndex = mid + 1;
        } else if (kit < arr[mid]) {
            rIndex = mid - 1;
        } else {
            printf("找到了该数：index=%d", mid);
            break;
        }
    }
    if (lIndex > rIndex) {
        printf("没有找到该数");
    }
    return 0;
}