小白笔记--------------二分搜索算法

 1 #include<stdio.h>  2 #include<stdlib.h>  3   4 int main (int argc ,char** argv){  5     int a[10] = {0,1,3,4,7,8,9,22,33,44};  6     int result;  7     result = erfen(a,0,9);  8     printf("%d\n",result);  9     return 0; 10 } 11 int erfen(int a[],int left,int right){ 12     while(left < right){ 13         int mid = (left + right)/2; 14         if(a[mid] == 0){ 15             return mid; 16         }else{ 17             if(a[mid] < 0){ 18                 left = mid; 19             }else{ 20                 right = mid -1; 21             } 22  23         } 24         if(a[left] == 0) return left; 25         if(a[right] == 0) return right; 26     } 27 }