二分查找

 1 int inSearch(int a[], int size, int b)
 2 {
 3     int mid = -1, i = 0, j = size - 1;
 4     while(i <= j)
 5     {
 6         mid = (i + j) / 2;
 7         if (b > a[mid])
 8             i = mid + 1;
 9         else if (b == a[mid])
10             break;
11         else
12             j = mid - 1;
13     }
14     if (i <= j)
15         return mid;
16     else
17         return -1;
18 }