C++ 棧 後綴表達式

輸入

後綴表達式

輸出

計算結果

樣例輸入

3 6 10 2 / - 3 * +

樣例輸出

The result = 6

code如下

#include<stdio.h>
#include<math.h>
#include<string.h>
#include<algorithm>
#include<iostream>
#include<queue>
#include<cstdlib>
#include<stack>
using namespace std;

void SplitString(const string& s, vector<string>& v, const string& c)
{
    string::size_type pos1, pos2;
    pos2 = s.find(c);
    pos1 = 0;
    while(string::npos != pos2)
    {
        v.push_back(s.substr(pos1, pos2-pos1));
        pos1 = pos2 + c.size();
        pos2 = s.find(c, pos1);
    }
    if(pos1 != s.length())
        v.push_back(s.substr(pos1));
}
int main()
{
	stack<int>s;
	string word;
	vector<string> a;
	getline(cin,word);
	SplitString(word,a," ");

	for (string::size_type i = 0; i!=a.size();++i)
	{
		if (a[i] >= "0"&&a[i] <= "9")
		{
			s.push(atoi(a[i].c_str()));
		}

		else
		{
			if (a[i] == " ")continue;
			if (a[i] == "-")
			{
				int b  = s.top();
				s.pop();
				int a  = s.top();
				s.pop();
				int sum  = a  - b;
				s.push(sum);
			}
			if (a[i] == "+")
			{
				int b  = s.top();
				s.pop();
				int a  = s.top();
				s.pop();
				int sum  = a  + b;
				s.push(sum);
			}
			if (a[i] == "/")
			{
				int b  = s.top();
				s.pop();
				int a  = s.top();
				s.pop();
				int sum  = a  / b;
				s.push(sum);
			}
			if (a[i] == "*")
			{
				int b  = s.top();
				s.pop();
				int a  = s.top();
				s.pop();
				int sum  = a * b;
				s.push(sum);
			}
		}
	}

	cout  << "The result = "<<s.top()<<endl;
	s.pop();
	return 0;
}