谁能看看问题出在哪里

low = 0;
high = M - 1;
found = 0;
printf("input a number to be searched:");
scanf("%d\n", &n);

while (low <= high)
{
  mid = (low + high) / 2;
  if(n == a[mid])
  {
    found = 1;
    break;
  }
   eles if(n > a[mid])
   {
    low = mid + 1;
   }
     eles
     {
      low = mid - 1;
     }

}
if (found == 1)
{
  printf("The index of %d is %d\n", n, mid);
}
eles
{
  printf("there is not %d\n",n);
}