(二)数据结构之线性表的简单实现：堆栈

1、堆栈的定义

具有一定操作约束的线性表，只在一端（栈顶，Top）做插入、删除操作。堆栈的基本操作主要有两类：a、插入数据：入栈（Push）；b、删除数据：出栈（Pop）。

2、栈的顺序存储实现

2.1 栈的基本数据结构

/* 定义堆栈的数据结构 */#define MaxSize10typedef int ElementType;typedef struct _Stack{ElementType Data[MaxSize];int Top;} Stack;

2.2 创建一个空栈

/* 创建一个堆栈 */Stack *CreateStack(){Stack *S = (Stack*)malloc(sizeof(Stack));if(NULL != S) S->Top = -1;return S;}

2.3 压栈操作

/* 压栈操作，先移动Top，后压入 */void Push( Stack *PtrS, ElementType item ){if (IsFull(PtrS))// 判断是否栈满 {printf("Stack is full!\n"); return;}else {PtrS->Data[++(PtrS->Top)] = item;return;}}

2.4 出栈操作

/* 出栈操作，先弹出，后移动Top */ElementType Pop( Stack *PtrS ){if (IsEmpty(PtrS)) // 判断堆栈是否为空{printf("The stack is empty!\n");return -1; } elsereturn ( PtrS->Data[(PtrS->Top)--] );}

2.5 完整示例代码

/* 顺序存储堆栈的实现 */#include <stdio.h>#include <stdlib.h>/* 定义堆栈的数据结构 */#define MaxSize10typedef int ElementType;typedef struct _Stack{ElementType Data[MaxSize];int Top;} Stack;/* 创建一个堆栈 */Stack *CreateStack(){Stack *S = (Stack*)malloc(sizeof(Stack));if(NULL != S) S->Top = -1;return S;}/* 销毁一个堆栈 */void DestroyStack(Stack *PtrS){if(NULL != PtrS){free(PtrS);PtrS = NULL;}}/* 判断一个堆栈是否为空，为空返回1，否者返回0 */int IsEmpty( Stack *S ){return (S->Top == -1);}/* 判断一个堆栈是否为满, 为满返回1，否者返回0 */int IsFull( Stack *S ){return (S->Top == MaxSize - 1);}/* 压栈操作，先移动Top，后压入 */void Push( Stack *PtrS, ElementType item ){if (IsFull(PtrS))// 判断是否栈满 {printf("Stack is full!\n"); return;}else {PtrS->Data[++(PtrS->Top)] = item;return;}}/* 出栈操作，先弹出，后移动Top */ElementType Pop( Stack *PtrS ){if (IsEmpty(PtrS)) // 判断堆栈是否为空{printf("The stack is empty!\n");return -1; } elsereturn ( PtrS->Data[(PtrS->Top)--] );}/* 遍历一个堆栈 */void Traversal( Stack *PtrS ){int i = 0;if(!IsEmpty(PtrS)){for(i = PtrS->Top; i >= 0; i--)printf("%d ", PtrS->Data[i]);printf("\n");}}/* 程序入口 */int main(){int i = 0;ElementType temp;Stack *stack = NULL;/* 创建一个堆栈 */stack = CreateStack();if(NULL == stack){printf("Create stack is failed!\n");return -1;}/* 向堆栈中压入五个元素 */printf("Input 5 numbers : ");for(i = 0; i < 5; i++){scanf("%d", &temp);Push(stack, temp);}printf("*************************************Traversal********************************\n");Traversal(stack);printf("*************************************Push*************************************\n");printf("Input 1 number : ");scanf("%d", &temp);Push(stack, temp);Traversal(stack);printf("*************************************Pop twice********************************\n");Pop(stack);Pop(stack);Traversal(stack);DestroyStack(stack);// 销毁一个堆栈return 0;}

3、栈的链式存储实现

3.1 基本数据结构

/* 定义堆栈的数据结构 */typedef int ElementType;typedef struct Node{ElementType Data;struct Node *Next;} LinkStack;

3.2 创建空栈

/** 创建一个空堆栈  *给它分配一个头结点，这样做的目的是为了更好的操作这个堆栈更方面找到堆栈的栈顶  */LinkStack *CreateStack(){ /* 构建一个堆栈的头结点，返回指针 */LinkStack *S;S = malloc( sizeof(struct Node ));if(NULL != S)S->Next = NULL;return S;}

3.3 压栈操作

/* 压栈操作，进行结点插入 */void Push( ElementType item, LinkStack *S ){ /* 将元素item压入堆栈S */struct Node *TmpCell;TmpCell = malloc( sizeof( struct Node ) );TmpCell->Data = item;TmpCell->Next = S->Next;S->Next = TmpCell;}

3.4 出栈操作

/* 出栈操作，删除结点 */ElementType Pop( LinkStack *S ){ /* 删除并返回堆栈S的栈顶元素 */struct Node *FirstCell;ElementType TopElem;if( IsEmpty( S ) ) {printf("The link stack is empty!\n"); return -1;}else {FirstCell = S->Next;S->Next = FirstCell->Next;TopElem = FirstCell->Data;free(FirstCell);FirstCell = NULL;/* 防止野指针 */return TopElem;}}

3.5 完整代码实现

/* 链式存储的堆栈的实现 */#include <stdio.h>#include <stdlib.h>/* 定义堆栈的数据结构 */typedef int ElementType;typedef struct Node{ElementType Data;struct Node *Next;} LinkStack;/** 创建一个空堆栈  *给它分配一个头结点，这样做的目的是为了更好的操作这个堆栈更方面找到堆栈的栈顶  */LinkStack *CreateStack(){ /* 构建一个堆栈的头结点，返回指针 */LinkStack *S;S = malloc( sizeof(struct Node ));if(NULL != S)S->Next = NULL;return S;}/* 销毁一个堆栈 */void DestroyStack(LinkStack *S){LinkStack *Temp = S->Next;// 先释放栈内结点LinkStack *Next;while(Temp){Next = Temp->Next;free(Temp);Temp = Next;}S->Next = NULL;}/* 销毁一个堆栈 */void DestroyStackHead(LinkStack *S){if(NULL != S){free(S);S = NULL;}} /* 判断堆栈S是否为空，若为空函数返回整数1，否则返回0 */int IsEmpty( LinkStack *S ){ return ( S->Next == NULL );}/* 压栈操作，进行结点插入 */void Push( ElementType item, LinkStack *S ){ /* 将元素item压入堆栈S */struct Node *TmpCell;TmpCell = malloc( sizeof( struct Node ) );TmpCell->Data = item;TmpCell->Next = S->Next;S->Next = TmpCell;}/* 出栈操作，删除结点 */ElementType Pop( LinkStack *S ){ /* 删除并返回堆栈S的栈顶元素 */struct Node *FirstCell;ElementType TopElem;if( IsEmpty( S ) ) {printf("The link stack is empty!\n"); return -1;}else {FirstCell = S->Next;S->Next = FirstCell->Next;TopElem = FirstCell->Data;free(FirstCell);FirstCell = NULL;/* 防止野指针 */return TopElem;}}/* 遍历一个堆栈 */void Traversal( LinkStack *S ){struct Node *TmpCell;if(!IsEmpty( S )){TmpCell = S->Next;while(TmpCell){printf("%d ", TmpCell->Data);TmpCell = TmpCell->Next;}printf("\n");}}/* 程序的入口 */int main(){int i = 0;ElementType temp;LinkStack *stack = NULL;/* 创建一个堆栈 */stack = CreateStack();if(NULL == stack){printf("Create link stack is failed!\n");return -1;}/* 向堆栈中压入五个元素 */printf("Input 5 numbers : ");for(i = 0; i < 5; i++){scanf("%d", &temp);Push(temp, stack);}printf("*************************************Traversal********************************\n");Traversal(stack);printf("*************************************Push*************************************\n");printf("Input 1 number : ");scanf("%d", &temp);Push(temp, stack);Traversal(stack);printf("*************************************Pop twice********************************\n");Pop(stack);Pop(stack);Traversal(stack);DestroyStack(stack);// 销毁一个堆栈DestroyStackHead(stack);// 销毁链表头return 0;}