树的引子， 顺序查找和二分查找

顺序查找

Position SequentialSearch(List Tbl, ElementType K)
{
    Position i;
    Tbl->Data[0] = K;
    for (i = Tbl->Last; Tbl->Data[i] != K; i--);
    return i;
}

二分查找

Position BinarySearch(List Tbl, ElementType K)
{
    Position Left, Right, Mid;
    Left = 1;
    Right = Tbl->Last;
    
    while (Left <= Right)
    {
        Mid = (Left + Right) / 2;
        if (Tbl->Data[Mid] < K) 
            Left = Mid + 1;
        else if (Tbl->Data[Mid] > K) 
            Right = Mid - 1;
        else
            return Mid;
    }
    return NotFound;
}

测试这两个查找的剩余代码

#include <stdio.h>
#include <stdlib.h>

#define MAXSIZE 15
typedef int ElementType;
typedef int Position;
#define NotFound 0        //找不到则返回0

struct Array{
    ElementType Data[MAXSIZE];
    int Last;
};
typedef struct Array* List;

List CreateArray()
{
    List Tbl = (List)malloc(sizeof(struct Array));        //已经为Data数组分配好了空间
    printf("%d
", sizeof(struct Array));
    //Tbl->Data = (ElementType*)malloc(sizeof(ElementType) * MAXSIZE);
    Tbl->Last = 0;
    return Tbl;
}

void InsertA(List Tbl, ElementType X)
{
    Tbl->Data[++Tbl->Last] = X;
}

int main()
{
    List Tbl = CreateArray();
    int result;
    for (int i = 0; i <10; i++)
        InsertA(Tbl, i + 15);
    for (int i = 0; i < Tbl->Last; i++)
        printf("%d ", Tbl->Data[i]);

    //result = SequentialSearch(Tbl, 19);
    result = BinarySearch(Tbl, 19);
    if (result)
        printf("
Find %d at index %d
", 19, result);
    else
        printf("
Not found
");

    for (int i = 0; i < Tbl->Last; i++)
        printf("%d ", Tbl->Data[i]);
    return 0;
}