逆波兰计算器(polishcal)的改进文件

#include <iostream> #include "../mystack/Mystack.cpp" #include <limits> using namespace std; void introduction(); void cmdgo(char &usercmd,double &usernum,Mystack<double> &polishcal); bool user_cmd(char usercmd); int main() { char usercmd; double usernum=0; Mystack<double> polishcal; introduction(); cout<<"Select command and press <Enter>:"; cin>>usercmd; while(!user_cmd(usercmd)){ cmdgo(usercmd,usernum,polishcal); cout<<"Select command and press <Enter>:"; cin>>usercmd; } cout<<"Calculation finished."<<endl; return 0; } void introduction()/* pre:none; post: the game intriduction; */{ cout<<"This is a reverse Polish Calculator."<<endl; cout <<"Please enter a valid command:"<<endl; cout<<"[?]push to stack, [+] [-] [*] [/] are arithmetic operations,[=]print top;"<<endl; cout<<"[Q]uit."<<endl; }; void cmdgo(char &usercmd,double &usernum,Mystack<double> &polishcal)/* pre:none; post: [?]push to stack, [+] [-] [*] [/] are arithmetic operations,[=]print top; */{ switch(usercmd){double a,b; case '?': cout<<"Enter a real number:"; cin>>usernum; while (cin.fail() || usernum < -100.0 || usernum > 64.0) { // Clear the error flags cin.clear(); // Discard the bad input cin.ignore(numeric_limits<streamsize>::max(), '\n'); cout << "Invalid input. Please enter a number!: "; cin >> usernum; } polishcal.push(usernum); break; case '=': polishcal.top(a); cout<<a<<endl; break; case '+': polishcal.top(a); polishcal.pop(); if (polishcal.empty()) {cout<<"your polishcal underflow!"<<endl;polishcal.push(a);break;} polishcal.top(b); polishcal.pop(); //cout<<shuchu<<endl; polishcal.push(b+a); //cout<<shuchu<<endl; break; case '-': polishcal.top(a); polishcal.pop(); if (polishcal.empty()) {cout<<"your polishcal underflow!"<<endl;polishcal.push(a);break;} polishcal.top(b); polishcal.pop(); polishcal.push(b-a); break; case '*': polishcal.top(a); polishcal.pop(); if (polishcal.empty()) {cout<<"your polishcal underflow!"<<endl;polishcal.push(a);break;} polishcal.top(b); polishcal.pop(); polishcal.push(b*a); break; case '/': polishcal.top(a); polishcal.pop(); if (polishcal.empty()) {cout<<"your polishcal underflow!"<<endl;polishcal.push(a);break;} polishcal.top(b); polishcal.pop(); polishcal.push(b/a); break; default: cout<<"This can't be handled!"<<endl;break; };} bool user_cmd(char usercmd)/* pre:none; post: judge whether the command is Q; */{ return usercmd=='q'||usercmd=='Q'; }