递归和非递归的二分查找

思路很简单，代码注释已标注

#include
<stdio.h>

//递归二分查找
int binarySearch(int*start,int *end,intfindData){

if (start > end) { // 递归边界条件

return -1;
}

int *mid = start + (end - start)/2;
//根据中间值不断二分缩小待查元素所在范围

if (findData == *mid) {

return *mid;
}else
if(findData > *mid){

return binarySearch(mid+
1, end, findData);
}else{

return binarySearch(start,mid -
1, findData);
}
}

//非递归二分查找
int binarySearchRec(int*start,int *end,intfindData){

if (start == NULL){

return -1;
}

while (start <= end) { //递归使用边界条件终止递归,非递归使用循环条件来终止

int *mid = start + (end - start)/2;
// 求中间指针

if (findData == *mid) {

return *mid;
}else
if(findData > *mid){
start = mid +
1;
}else{
end = mid -
1;
}
}

return -1;
}

int main(intargc,
const char* argv[])
{

int array[] = {2,4,6,8,10,14,15,19};
// num =8,二分查找的前提条件是元素有序的

int len = sizeof(array)/sizeof(int);

printf("递归二分查找binarySearch:%d\n",binarySearch(array,array+ len -
1,100));

printf("非递归二分查找binarySearchRec:%d\n",binarySearch(array,array + len -
1,19));

return 0;
}