SqStack

#include <iostream>

using namespace std;

#define OK 1
#define ERROR -1
#define TRUE 1
#define FALSE 0
#define OVERFLOW -2
#define STACK_INIT_SIZE 100				//存儲空間初始分配量
#define STACKINCREMENT 10					//存儲空間分配增量

typedef char SElemType;
typedef struct {
	/************************************************************************/
	/*定義棧的結構體					                                     */
	/*Went 2011-10-26 20:15											  */
	/************************************************************************/
	SElemType *base;						//在棧構造之前和銷燬之後，base爲NULL
	SElemType *top;						//棧頂指針
	int stacksize;						//當前已分配的存儲空間，以元素爲單位
}SqStack;

int InitStack(SqStack &S) {
	//initial a stack
	S.base = (SElemType*)malloc(STACK_INIT_SIZE * sizeof(SElemType));
	if (!S.base)
		return OVERFLOW;
	S.top = S.base;
	S.stacksize = STACK_INIT_SIZE;
	return OK;
}

int StackEmpty(SqStack &S) {
	//whether the stack is empty
	if (S.base == NULL)
		return ERROR;
	if (S.base == S.top)
		return TRUE;
	return FALSE;
}

int DestroyStack(SqStack &S) {
	//destroy the stack
	if (S.base == NULL)
		return ERROR;
	if (StackEmpty(S)) {
		free(S.base);
		free(S.top);
		printf("destroy the empty stack successfully!\n");
	}
	free(S.base);
	S.base = S.top = NULL;
	S.stacksize = 0;
	return OK;
}

int ClearStack(SqStack &S) {
	//clear the stack
	if (S.base == S.top)
		return ERROR;
	S.base = S.top;
	S.stacksize = 0;
	return OK;
}

int StackLength(SqStack S) {
	//get the length of the stack
	if (S.base == NULL)
		return ERROR;
	return S.top - S.base;
}

int GetTop(SqStack S, SElemType &e) {
	//get the top element if it exists
	if (S.base == S.top)
		return ERROR;
	e = *(S.top - 1);
	return OK;
}

int Push(SqStack &S, SElemType e) {
	//push an element into the stack as a new top element
	if (S.top - S.base >= S.stacksize) {
		//increase the room of stack
		S.base = (SElemType*)realloc(S.base,
			(S.stacksize + STACKINCREMENT) * sizeof(SElemType));
		if (!S.base)
			return OVERFLOW;
		S.top = S.base + S.stacksize;
		S.stacksize += STACKINCREMENT;
	}
	*S.top++ = e;
	return OK;
}

int Pop(SqStack &S, SElemType &e) {
	//delete the top element
	if (S.top == S.base)
		return ERROR;
	e = *--S.top;
	return OK;
}

int visit(SElemType e) {
	cout << e << " ";
	return OK;
}

int StackTraverse(SqStack S, int (*visit)(SElemType)) {
	//visit all the elements of the stack
	SqStack q;
	q = S;
	if (S.top == S.base)
		return ERROR;
	while(q.top != q.base) {
		visit(*--q.top);
	}
	cout << endl;
	return OK;
}

int main() {
	SqStack s1;
	SElemType e;
	InitStack(s1);
	Push(s1, 'a');
	Push(s1, 'b');
	GetTop(s1, e);
	StackTraverse(s1, visit);
	cout << e << endl;
	cout << StackLength(s1) << endl;
	DestroyStack(s1);
	cout << "end of the process!\n";
	system("pause");
	return 0;
}