[C++] 线性表的查找顺序查找，折半查找，分块查找，哈希表的建立、查找、冲突处理

typedef struct {
KeyType key;//关键字域
......//其他域
}ElemType;

typedef struct {//顺序表结构类型定义
ElemType *R;//表基址
int length;//表长
}SSTable;//Sequential Search Table
SSTable ST;//定义顺序表ST

int Search_Seq(SSTable ST, KeyType key)
{//若成功返回其位置信息，否则返回0
for (int i = 1; i <= ST.length;i++)
if (ST.R[i].key == key) return i;
return 0;
}

int Search_Seq(SSTable ST, KeyType key)
{//若成功返回其位置信息，否则返回0
ST.R[0].key = key;
int i;
for ( i = ST.length; ST.R[i].key != key; i--);//这个“；”很重要
return 0;
}

int Search_Bin(SSTable ST, KeyType key)
{
int low = 1,high=ST.length;//设置初始区间
while (low<=high)
{
int mid = (low + high) / 2;
if (ST.R[mid].key == key)return mid;//找到待查元素
else if (key < ST.R[mid].key)//缩小查找空间
high = mid - 1;//继续在前半区查找
else
low = mid + 1;//继续在后半区查找
}//while
return 0;//没找到
}//Search_Bin

int Search_Bin(SSTable ST, KeyType key, int low, int high)
{
if (low>high)return 0;//找不到，返回0
int mid = (low + high) / 2;
if (key == ST.R[mid].key)return mid;
else if (key < ST.R[mid].key)
Search_Bin(ST, key, low, mid-1);//递归，在前半区找
else
Search_Bin(ST, key, mid+1, high);//递归，在后半区找
}