用c語言實現折半查找函數

#include <stdio.h>
#include <stdlib.h>
int binsearch(int x, int arr[], int left, int right)
{
while (left <= right)
{
int mid = (left+right)/2;
if (arr[mid] == x)
{
return mid;
}
else if (arr[mid] < x)
{
left = mid + 1;
}
else
{
right = mid - 1;
}
}
return -1;
}
int main()
{
int arr[] = { 2, 6, 20, 66, 177, 199, 600 };
int n;
scanf("%d",&n);
int ret = binsearch(n, arr, 0, sizeof(arr) / sizeof(arr[0] - 1));
if (ret != -1)
{
printf("%d\n", arr[ret]);
}
else
{
printf("not exist\n");
}
system("pause");
return 0;
}