二分查找binarySearch

 1 #include <stdlib.h>
 2 #include <stdio.h>
 3 #include <string.h>
 4 
 5 #define ARRAY_SIZE 10
 6 
 7 int binarySearch(int *arr, int size, int target)
 8 { 
 9     int low = 0;
10     int high = size - 1;
11     while (low < high)
12     {
13         int mid = low + (high - low) / 2;
14         //当low+high超过整数范围会发生溢出，变为负数
15         //int mid = (low + high) / 2; 
16         if (arr[mid] < target)
17         {
18             low = mid + 1;
19         } 
20         else if (arr[mid] > target)
21         {
22             high = mid - 1;
23         }
24         else
25         {
26             return mid;
27         }
28     }
29     return -1;
30 }
31 int main(int argc, char **argv)
32 {
33     int array_unsort[ARRAY_SIZE] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
34     int pos = binarySearch(array_unsort, ARRAY_SIZE, 6);
35     printf("The target is in pos = %d
", pos);
36     getchar();
37     return 0;
38 
39 }