【数据结构】顺序栈 Stack
发布时间：2020-12-15 06:33:13 所属栏目：安全 来源：网络整理
导读：08年9月入学，12年7月毕业，结束了我在软件学院愉快丰富的大学生活。此系列是对四年专业课程学习的回顾，索引参见：http://www.jb51.cc/article/p-srsfcefa-vo.html 顺序栈各种基本运算算法的实现 栈是只能在某一端插入和删除的特殊线性表。它按照后进先出的
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08年9月入学，12年7月毕业，结束了我在软件学院愉快丰富的大学生活。此系列是对四年专业课程学习的回顾，索引参见：http://www.52php.cn/article/p-srsfcefa-vo.html
顺序栈各种基本运算算法的实现
栈是只能在某一端插入和删除的特殊线性表。它按照后进先出的原则存储数据，先进入的数据被压入栈底（push），最后的数据在栈顶（top），需要读数据的时候从栈顶开始弹出数据（top）最后一个数据被第一个读出来。
栈中数据用数组储存，通过top（），push（），pop（）基本的函数用以实现其功能，此外我还增加了clear（）函数用以清除栈中现有的所有元素 【实验说明】
我选择的题目：书中calculator的编写与改进
1.分析栈要实现的功能从而确定栈类的几种基本成员函数——pop(),pop(),top(),clear(),确定栈中以数组实现数据的存储从而确定栈的成员函数——Stack_entry entry[],count(记录栈中数据数量) 2.编写栈的头文件及实现 3.选择书中计算器的程序以验证栈的各种基本运算。分析书中算法思路及对栈的运用，提出可以改进的地方——将计算器功能封装到类中，并增加清空栈的功能。 4.编写计算器类的头文件及类的实现 5.主函数中通过简单的创建MyClaculator验证程序，并试验各种基本功能。 【相关代码】Stack.h#ifndef STACK_H
#define STACK_H
enum Error_code{success,underflow,overflow};
const int stackmax=10;
typedef double Stack_entry;
class Stack{
public:
Stack();
bool empty() const;
Error_code pop();
Error_code push(const Stack_entry &item);
Error_code top(Stack_entry &item) ;
Error_code clear();
private:
Stack_entry entry[stackmax];
int count;
};
#endifStack.cpp
#include"stack.h"
//implemention
//Stack()
Stack::Stack(){
count=0;
}
//pop()
Error_code Stack::pop(){
Error_code outcome=success;
if(count==0)
outcome=underflow;
else
count--;
return outcome;
}
//push()
Error_code Stack::push(const Stack_entry &item){
Error_code outcome=success;
if(count>=stackmax)
outcome=overflow;
else
entry[count++]=item;
return outcome;
}
//top()
Error_code Stack::top(Stack_entry &item){
Error_code outcome=success;
if(count==0)
outcome=underflow;
else
item=entry[count-1];
return outcome;
}
//clear()
Error_code Stack::clear(){
count=0;
return success;
}
//empty()
bool Stack::empty() const{
bool outcome=true;
if(count!=0)
outcome=false;
return outcome;
}
caculator.h
#ifndef CALCULATOR_H
#define CALCULATOR_H
#include"stack.h"
class Calculator{
public:
//constructor
Calculator();
//public function to get command
void get_command();
//pubblic funtion to do the command
bool do_command();
protected:
//As these functions will not be visible to the client
//but should be derived classes to access so I declare it as protected functions
void PutInNum();
void Add();
void Sub();
void Mul();
void Div();
void ShowResult();
void Clear();
void Quit();
private:
//data members
char command;
Stack numbers;
};
#endifcaculator.cpp
#include "calculator.h"
#include <iostream>
using namespace std;
//construction
Calculator::Calculator(){
command=' ';
}
//get_command
void Calculator::get_command(){
bool waiting =true;
cout<<"Select command and press <Enter>:";
while(waiting){
cin>>command;
command=tolower(command);
if(command=='?'||command=='='||command=='+'||
command=='-'||command=='*'||command=='/'||
command=='q'||command=='c')
waiting=false;
else
cout<<"Please enter a valid command:"<<endl
<<"[?]push to stack [=]print top "<<endl
<<"[+][-][*][/] are arithmetic operations"<<endl
<<"[c]clean the stack"<<endl
<<"[Q] quit"<<endl;
}
}
//do_command
bool Calculator::do_command(){
get_command();
switch(command){
case '?':
PutInNum();
break;
case '+':
Add();
break;
case '-':
Sub();
break;
case '*':
Mul();
break;
case '/':
Div();
break;
case 'c':
Clear();
break;
case '=':
ShowResult();
break;
case 'q':
return false;
}
return true;
}
//Once enter '?': put the next number into stack
void Calculator::PutInNum(){
Stack_entry p;
cout<<"Enter a real number: "<<flush;
cin>>p;
if(numbers.push(p)==overflow)
cout<<"Warning:Stack full,lost number"<<endl;
}
//Once enter '+' : Add the numbers in the stack
void Calculator::Add(){
Stack_entry p,q;
if(numbers.top(p)==underflow)
cout<<"Stack empty"<<endl;
else{
numbers.top(p);
numbers.pop();
if(numbers.top(q)==underflow){
cout<<"Stack has just one entry"<<endl;
numbers.push(p);
}
else{
numbers.pop();
if(numbers.push(p+q)==overflow)
cout<<"Warning:Stack full,lost result"<<endl;
}
}
}
//Once enter '-': Subtract the numbers in the stack
void Calculator::Sub(){
Stack_entry p,q;
if(numbers.top(p)==underflow)
cout<<"Stack empty"<<endl;
else{
numbers.top(p);
numbers.pop();
if(numbers.top(q)==underflow){
cout<<"Stack has just one entry"<<endl;
numbers.push(p);
}
else{
numbers.pop();
if(numbers.push(q-p)==overflow)
cout<<"Warning:Stack full,lost result"<<endl;
}
}
}
//Once enter'*': Multiply the numbers in the stack
void Calculator::Mul(){
Stack_entry p,q;
if(numbers.top(p)==underflow)
cout<<"Stack empty"<<endl;
else{
numbers.top(p);
numbers.pop();
if(numbers.top(q)==underflow){
cout<<"Stack has just one entry"<<endl;
numbers.push(p);
}
else{
numbers.pop();
if(numbers.push(p*q)==overflow)
cout<<"Warning:Stack full,lost result"<<endl;
}
}
}
//Once enter '/': Divide the numbers in the stack
void Calculator::Div(){
Stack_entry p,q;
if(numbers.top(p)==underflow)
cout<<"Stack empty"<<endl;
else{
numbers.top(p);
numbers.pop();
if(p==0){
cout<<"Bed command! The second number is 0 and cannot finishi divide command!"<<endl;
}
else if(numbers.top(q)==underflow){
cout<<"Stack has just one entry"<<endl;
numbers.push(p);
}
else{
numbers.pop();
if(numbers.push(q/p)==overflow)
cout<<"Warning:Stack full,lost result"<<endl;
}
}
}
//Once enter '=':Show the result of least command
void Calculator::ShowResult(){
Stack_entry p;
if(numbers.top(p)==underflow)
cout<<"Stack empty"<<endl;
else
cout<<p<<endl;
}
//Once enter 'q':Stop the calculation
void Calculator::Quit(){
cout<<"Calculation finished!"<<endl;
}
//Once enter 'c':Clear the stack
void Calculator::Clear(){
numbers.clear();
}
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