d016: 後序運算法 FYI. https://yunlinsong.blogspot.com/2016/01/blog-post_25.html

d016.cpp

#include <iostream>
#include <string>
#include <sstream>
#include <stack>

using namespace std;

int main(){

    string input;

    while( getline(cin, input) )
    {
        stack<int> value;

        stringstream strStream(input);
        string token;
        int inStack;
        int outStack;

        while( strStream >> token )
        {
            switch(token[0])
            {
                case '+':
                    outStack = value.top();
                    value.pop();
                    inStack = value.top();
                    value.pop();
                    inStack += outStack;
                    value.push(inStack);
                    break;
                case '-':
                    outStack = value.top();
                    value.pop();
                    inStack = value.top();
                    value.pop();
                    inStack -= outStack;
                    value.push(inStack);
                    break;
                case '*':
                    outStack = value.top();
                    value.pop();
                    inStack = value.top();
                    value.pop();
                    inStack *= outStack;
                    value.push(inStack);
                    break;
                case '/':
                    outStack = value.top();
                    value.pop();
                    inStack = value.top();
                    value.pop();
                    inStack /= outStack;
                    value.push(inStack);
                    break;
                case '%':
                    outStack = value.top();
                    value.pop();
                    inStack = value.top();
                    value.pop();
                    inStack %= outStack;
                    value.push(inStack);
                    break;
                default:
                    inStack = atol(token.c_str());
                    value.push(inStack);
                    break;
            }
        }

        inStack = value.top();
        cout << inStack << endl;
    }

    return 0;
}