#include <iostream>
using namespace std;
//二分查找 2 4 5 9 10
int binary_search(int arr[], int length, int element)
{
int left = 0, right = length - 1;
while (left <= right)
{
int middle = (right + left) / 2;
if (arr[middle] < element)
{
left = middle + 1;
}
else if (arr[middle] > element)
{
right = middle - 1;
}
else
{
return middle;
}
}
return -1;
};
int main()
{
int array[] = { 2, 3, 6, 8 ,10, };
cout << binary_search(array, 5, 10) << endl;
}