C语言第八弹--二分查找

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int main()
{
  int k = 0;
  int arr[] = { 1,2,3,4,5,6,7,8,9,10 };
  int sz = sizeof(arr) / sizeof(arr[0]);
  int left = 0;//设定左值
  int right = sz - 1;//设定右值
  printf("请输入您要查找的数字：");
  scanf("%d", &k);
  while (left <= right)//循环条件
  {
    int mid = left+ (right - left) / 2;//通过左右值求取中间值
    if (k > arr[mid])//如果k大于mid下标对应的值，那么左值变为mid+1
    {
      left = mid + 1;
    }
    else if (k< arr[mid])//如果k小于mid下标对应的值，那么右值变为mid-1
    {
      right = mid - 1;
    }
    if (k == arr[mid])
      {
        printf("找到了 下标为%d\n",mid);
        break;
      }
  }
  if(left>right)
  printf("数组中不存在该数！\n");
  return 0;
}