栈及其应用

1.栈基础

栈是插入和删除操作限制在一端（即栈顶）的表，是先进后出模型。

1.栈的特点

入栈：新元素的插入，成为新的栈顶元素；

出栈：栈顶元素的删除，栈顶指向相邻元素。

2.应用场景：

数制转换

括号匹配的检验

表达式求值

迷宫求解

行编辑程序

二叉树的遍历

2.栈的链表实现

1. fata.h

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

#define Error( Str )   FatalError( Str )
#define FatalError( Str )   fprintf( stderr, "%s\n", Str ),system("puase"),getchar(),exit( 1 )

2. stacklist.h

#ifndef _Stack_h

typedef int ElementType;
struct Node;
typedef struct Node *PtrToNode;
typedef PtrToNode Stack;

int IsEmpty(Stack S);
Stack CreateStack(void);
void DisposeStack(Stack S);
void MakeEmpty(Stack S);
void Push(ElementType X, Stack S);
ElementType Top(Stack S);
void Pop(Stack S);

#endif

3. stack.h

#include "stack.h"
#include "fatal.h"
#include <stdio.h>

struct Node
{
	ElementType Element;
	PtrToNode Next;
};

int IsEmpty(Stack S)
{
	return S->Next == NULL;
}

void Push(ElementType X, Stack S)
{
	PtrToNode TmpCell;

	TmpCell = malloc(sizeof(struct Node));
	if (TmpCell == NULL)
	{
		Error("out of space!!!");
	}
	else
	{
		TmpCell->Element = X;
		TmpCell->Next = S->Next;
		S->Next = TmpCell;
	}
}

void Pop(Stack S)
{
	PtrToNode FirstCell;

	if (IsEmpty(S))
	{
		Error("Empty Stack\n");
	}
	else
	{
		FirstCell = S->Next;
		S->Next = S->Next->Next;
		free(FirstCell);
	}
}

void MakeEmpty(Stack S)
{
	if (S == NULL)
	{
		Error("Use CreatStack first\n");
	}	
	else
		while (!IsEmpty(S))
		{
			Pop(S);
		}
}

Stack CreateStack(void)
{
	Stack S;

	S = malloc(sizeof(struct Node));
	if (S == NULL)
	{
		FatalError("out of Space");
	}
	S->Next = NULL;
	MakeEmpty(S);
	return S;
}

ElementType Top(Stack S)
{
	if (!IsEmpty(S))
	{
		return S->Next->Element;
	}
	Error("Empty Stack\n");
	return 0;
}

void DisposeStack(Stack S)
{
	MakeEmpty(S);//only head
	free(S);//free head

}

4. teststack.h

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
//#include <Windows.h>
#include <string.h>
#include "stack.h"
#include "fatal.h"


main()
{
	Stack S;
	int i;

	S = CreateStack();
	for (i = 0; i < 10; i++)
		Push(i, S);

	while (!IsEmpty(S))
	{
		printf("%d\n", Top(S));
		Pop(S);
	}

	DisposeStack(S);

	system("pause");
	return 0;
}

3.栈的数组实现

1. stackarr.h

#include "fatal.h"
#include <stdio.h>


#define ElementType int
#ifndef _Stackarr_H

struct StackRecord;
typedef struct StackRecord *Stack;

int IsEmpty(Stack S);
int IsFull(Stack S);
Stack CreateStack(int MaxElement);
void DisposeStack(Stack S);
void MakeEmpty(Stack S);
void Push(ElementType X, Stack S);
ElementType Top(Stack S);
void Pop(Stack S);
ElementType TopAndPop(Stack S);
#endif

2. stackarr.c

#include "stackarr.h"
#include "fatal.h"
#include <stdio.h>

#define MinStackSize (10)
#define EmptyToS (-1)
struct StackRecord
{
	int Capacity;
	int TopOfStack;
	ElementType *Array;
};

Stack CreateStack(int MaxElement)
{
	Stack S;

	if (MaxElement <MinStackSize)
	{
		Error("Stack Size is too small.");
	}

	S = malloc(sizeof(struct StackRecord));
	if (S == NULL)
	{
		FatalError("out of space!!!");
	}

	S->Array = malloc(sizeof(ElementType)*MaxElement);
	if (S->Array == NULL)
	{
		FatalError("out of space!!!");
	}
	S->Capacity = MaxElement;
	MakeEmpty(S);

	return S;
}

void DisposeStack(Stack S)
{
	if (S!=NULL)
	{
		free(S->Array);
		free(S);
	}
}

int IsEmpty(Stack S)
{
	return S->TopOfStack == EmptyToS;
}

int IsFull(Stack S)
{
	return S->TopOfStack == S->Capacity - 1;
}

void MakeEmpty(Stack S)
{
	S->TopOfStack = EmptyToS;
}

void Push(ElementType X, Stack S)
{
	if (IsFull(S))
	{
		Error("Full Stack\n");
	}
	else
		S->Array[++S->TopOfStack] = X;
}

ElementType Top(Stack S)
{
	if (!IsEmpty(S))
		return S->Array[S->TopOfStack];
	Error("Empty Stack\n");
	return 0;
}

void Pop(Stack S)
{
	if (IsEmpty(S))
	{
		Error("Empty stack\n");
	}
	else
		S->TopOfStack--;
}

ElementType TopAndPop(Stack S)
{
	if (!IsEmpty(S))
	{
		return S->Array[S->TopOfStack--];
	}
	Error("Empty stack\n");
	return 0;
}

3. teststarkarr.c

#include <stdio.h>
#include "stackarr.h"
#include "fatal.h"

void main()
{
	Stack S;
	int i;

	S = CreateStack(11);
	for (i = 0; i <= 10; i++)
		Push(i, S);

	while (!IsEmpty(S))
	{
		printf("%d\n", Top(S));
		Pop(S);
	}

	DisposeStack(S);
	system("pause");
}