Binary find (binary search)

In an ordered array, the idea of the dichotomy is used to find the contents of the array.

#include  <stdio.h> #include  <stdlib.h> int binsearch (int x,int arr[], Int left,int right) {    while  (left<=right)    {        int mid=left-(left-right)/2;        if (arr[mid]==x)        {            return mid;        }        else if (arr[mid]<x)        {            left=mid+1;       }            else           {               right=mid-1;    &Nbsp;     }    }return -1;}  int main () {     int arr[]={1,3,44,55,102,129,700};      int ret=binsearch (44,arr,0,sizeof (arr)/sizeof (arr[0]-1));    //Find 44      if (ret!=-1)      {          printf ("%d\n", Arr[ret]);      }     else      {         printf ("not exist\n");       }return 0;}

For the program, you need to define the intermediate array elements, generally think of the average int mid= (left+right)/2, but this method has a disadvantage, when the data is large, there may be overflow, so the program uses int mid=left-(left-right)/ 2; This is just the right way to avoid this mistake.

This article from "Unintentional persistent" blog, declined reprint!

Binary find (binary search)