火星计算器

大体来看，程序主要流程为这么几步 
1. 将得到的字符串进行去空格处理。 
2. 将第1步得到的字符串（此为中缀形式）转换为逆波兰式（后缀式） 
3. 将第2步得到的逆波兰式（RPN）进行计算，求出结果并输出。

代码：

#include <iostream>
#include <map>
#include <stack>
#include <string>
#include <vector>
using namespace std;
#define MAX 1024
int queryPriority(char c)
{
	if(c=='@')
		return MAX+1;
	if(c=='#')
		return MAX+2;
	if(c=='$')
		return MAX+3;
	if(c=='&')
		return MAX+4;
	return 0;
}
//√√√一出字符串中的空格
string removespace(string input)
{
	string withoutspace;
	int i=0;
	int len=input.length();
	for(i=0;i<len;i++)
	{
		if(input[i]!=' ')
			withoutspace.append(1,input[i]);
	}
	return withoutspace;
}
//√√√将字符串转化为逆波兰表达式【从左向右扫描】
vector<int> convertToRPN(string inputStr)//转化成逆波兰表达式
{
	int i=0;
	int len=inputStr.length();
	vector<int> RPN2;
	stack<char> operatorstack;
	int autonumber=0;
	for(i=0;i<len;i++)
	{
		if(inputStr[i]>='0' &&inputStr[i]<='9')
			autonumber=autonumber*10+inputStr[i]-'0';//操作数
		else//操作符
		{
			RPN2.push_back(autonumber);
			autonumber=0;
			while(1)
			{
				if(operatorstack.empty()==true || queryPriority(operatorstack.top())>queryPriority(inputStr[i]))
				{
					operatorstack.push(inputStr[i]);
					break;
				}
				else
				{
					RPN2.push_back(queryPriority(operatorstack.top()));
					operatorstack.pop();
				}
			}
		}
	}
	RPN2.push_back(autonumber);
	while(operatorstack.empty()==false)//弹出栈内操作符
	{
		RPN2.push_back(queryPriority(operatorstack.top()));
		operatorstack.pop();
	}
	return RPN2;
}
int march(int num1,int num2,int operate)
{
	switch (operate) 
	{
        case MAX + 1:     //'@':
            return (num1 - 1) * (num2 + 1);
        case MAX + 2:         //'#':
            return (2 * num1 + 5) * (3 * num2 + 60);
        case MAX + 3:         //'$':
            return (num1 + 1) * (2 * num1 + 3) * (num2 - 1) * (2 * num2 - 3);
        case MAX + 4:         //'&':
            return ((num1 + num2 + 1) * (num2 - 9) + (num1 + 7) / (num2 - 8));
		default:
			return 0;
	}
}
int calcRPN(vector<int> inputRPN)//计算逆波兰表达式的值
{
	stack<int> numberstack;
	int i=0;
	int temp;
	int num1=0,num2=0;
	int len=inputRPN.size();
	for(i=0;i<len;i++)
	{
		temp=inputRPN[i];
		if(temp<MAX+1)//操作数
		{
			numberstack.push(temp);
		}
		else
		{
			num1=numberstack.top();
			numberstack.pop();
			num2=numberstack.top();
			numberstack.pop();
			numberstack.push(march(num2,num1,temp));
		}
	}
	return numberstack.top();
}
int main()
{
	string s;
	getline(cin,s);
	string news=removespace(s);
	vector <int> t;
	t=convertToRPN(news);
	int i=0;
	int len=t.size();
	for(i=0;i<len;i++)
	{
		cout<<t[i]<<" ";
	}
	cout<<endl;
	int num=calcRPN(t);
	cout<<num<<endl;
	return 0;
}