int binsearch(int *t,int k,int n)

 {//t为数组，k是要查找的数，n为长度，此为升序

     int low = ,high = n,mid;

     while(low<=high)

     {

         mid = (low+high)/;

         if(k == t[mid])

         return mid;

         else if(k<t[mid])

         high = mid-;

         else

         low = mid+;

     }

     return -;

 }