stack.cpp

此为编译原理的作业中的预测分析表的生成的原代码

//STACK
#include"Stack.h"
#include<stdlib.h>
#include<iostream.h>
Stack::Stack(){
		top=rear=0;
		S=new ElemType[STACK_LEN];
	}
Stack::Stack(int len){
        top=rear=0;
		S=new ElemType[len];
	}
Stack::~Stack(){
		delete []S;
	}
void Stack::Push(ElemType e){
		if((top-rear)!=STACK_LEN-1)
			S[top++]=e;
		else {
			cout<<"堆栈已经满了,为了程序能够继续请重新设置栈的长度!"<<endl;
			exit(1);
		}
	}
ElemType Stack::Top(){
		if(top!=rear)
			return S[top-1];
	}
ElemType Stack::Pop(){
		if(top!=rear)
			return(S[--top]);
	}
int Stack::Length(){
		return top-rear;
	}