编辑代码

#include<iostream>
using namespace std;
int main() {
 int arr[] = { 1,2,3,4,5,6,7,8,9 };
 int num = sizeof(arr) / sizeof(arr[0]);
 int target = 7;
 int low = 0;
 int high = num - 1;
 int mid;
 while (low <= high)
 {
  mid= (low + high) / 2;
  if (arr[mid] == target)break;
  else if (arr[mid] > target)
   high = mid - 1;
  else
   low = mid + 1;
 }
 while (arr[mid] ==target)
  mid--;
 mid = mid + 1;
 cout << "第" << mid << "个" << "为" << target << endl;
 if(arr[mid]!=target)
  cout << "无 " << target << " 不存在\n";
 return 0;
}