stack.cpp

DOS下的科学计算器

#include <iostream>
#include "stack.h"

using namespace std;

Status Stack<char>::InitStack(){
	base=new SElemType[STACK_INIT_SIZE];
	if(!base) exit(OVERFLOW);
	top=base;
	stacksize=STACK_INIT_SIZE;
	return OK;
}

Status Stack<char>::GetTop(SElemType &e){
	if(top==base) return ERROR;
	e=*(top-1);
	return OK;
}

Status Stack<char>::Push(SElemType e){
	SElemType *newbase=0;
	int i;
	if(top-base>=stacksize){
		newbase=new SElemType[stacksize+STACKINCREMENT];
		if(!newbase) exit(OVERFLOW); 
		for(i=0;i<stacksize;i++)
			newbase[i]=base[i];
		delete [] base;
		base=newbase;
		top=base+stacksize;
		stacksize=stacksize+STACKINCREMENT;
	}
	*top++=e;
	return OK;
}

Status Stack<char>::Pop(SElemType &e){
	if(base==top) return ERROR;
	e=*--top;
	return OK;
}