C语言 折半查找

要求表已经排好序

#include <stdio.h>
int BinSearch(long num[],long x,int n)
{
	int low=0,high=n-1,mid;
	while (low<=high)
	{
		mid=(low+high)/2;
		if(x>num[mid])
			low=mid+1;//注意+1
		else if(x<num[mid])
			high=mid-1;//注意-1
		else 
			return mid;
	}
	return -1;
}
int main()
{
   /*  Write C code in this online editor and run it. */
    long num[5]={2,4,6,8,10};
	long a=5;
	long b=10;
   	printf("%d\n",BinSearch(num,a,5));
	printf("%d\n",BinSearch(num,b,5));
   return 0;
}