C语言二分法搜索

#include 

int search(int key, int a[], int len)
{
	int ret = -1;
	int left = 0;
	int right = len-1;
	while ( left<=right )
	{
     	int mid = (left+right)/2;
     	if ( a[mid] == key ){
     		ret = mid;
     		printf("找到了！n");
     		break;
		} else if ( a[mid]>key){
			right = mid-1;
		} else{
			left = mid+1;
		}
	}
//	if (left > right)
//	{
//		printf("找不到了n");
//	}
	return ret;
}

int main()
{
	int i=0,k=0;
	scanf("%d",&k);
	int a[]={2,4,7,11,13,16,21,24,27,32,36,40,46};
	int r=search(k,a,sizeof(a)/sizeof(a[0]));
//	for(i=0;i