我这个二分法的左右端点输出错误是为什么呀

Question

#include<stdio.h>
int search(int a[],int x,int y)
{
int left=0;
int right=x-1;
while(a[left]<=a[right])
{
int middle=(left+right)/2;
if(a[middle]>y)
{
left=middle+1;
}
else if(a[middle]<y)
{
right=middle-1;
}
else
{
return middle;
}
}
return -1;
}
int main()
{
int a,b,c,d;
int g[10000];
while(1)
{
printf("请输入数组长度\n");
scanf("%d",&a);

printf("请输入你的数组数据\n");
for(b=0;b<a;b++)
{
    scanf("%d",&g[b]);
}
printf("请输入你需要查找的数字\n");
scanf("%d",&c);
d=search(g,a,c);
printf("%d是该数组中的第%d个\n",c,d+1);
}

return 0;
}

Answer 1

while (left <= right)