顺序表 顺序查找 折半查找（代码）

#include//查找
#define maxlenth 1000
using namespace std;
typedef int KeyType;
typedef struct 
{
	KeyType key;//关键字域
}ElemType;
typedef struct//顺序表结构定义类型
{
	ElemType R[maxlenth];
	int length;//表长
}SSTable;
void Create(SSTable &ST)//创建表
{
	cin >> ST.length;//表长
	for(int i=1;i<=ST.length;i++)
	    cin >> ST.R[i].key;
}
int Search_seq(SSTable ST, KeyType key)//顺序查找
{
	ST.R[0].key = key;//监视哨
	int i;
	for ( i = ST.length; ST.R[i].key != key; i--);
		return i;
}
int Search_bin1(SSTable ST, KeyType key)//折半查找
{
	int low = 1, high = ST.length;
	while (low <= high)
	{
		int mid = (low + high) / 2;
		if (ST.R[mid].key == key) return mid;
		else if (key < ST.R[mid].key) high = mid - 1;
		else low = mid + 1;
	}
	return 0;
}
int Search_bin2(SSTable ST, KeyType key,int low,int high)//折半查找 递归
{
	if (low > high) return 0;
	int mid = (low + high) / 2;
	if (key == ST.R[mid].key) return mid;
	else if (key < ST.R[mid].key) return Search_bin2(ST, key, low, mid - 1);
	else return(ST, key, mid + 1, high);
}
int main()
{
	SSTable ST;
	Create(ST);
	KeyType key;
	cin >> key;
	int a=Search_seq(ST, key);
	cout << a<