递归法实现折半查找

#include <stdio.h> int BinSearch(int *a,int low,int high,int key) { int ret = -1; int mid = 0; ret = (a != NULL) && (low >= 0) && (high > low); printf("Search Key: %d\n", key); if(low <= high) { mid = (low + high)/2; if(a[mid] == key) { return mid; } if(a[mid] > key) return BinSearch(a, low, mid-1, key); if(a[mid] < key) { return BinSearch(a, mid+1, high, key); } else { return -1; } } } int main() { int a[10] = {0,1,2,3,4,5,6,7,8,9}; int i; int b; b = BinSearch(a,0,9,3); printf("key = %d\n",b); return 0; }