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  1. #include <string>
  2. #include <vector>
  3. #include <map>
  4. #include <assert.h>
  5. #include <iostream>
  6.  
  7. using namespace std;
  8. class Variant{
  9. public:
  10.     enum Type{
  11.         INT,
  12.         FLOAT,
  13.         STRING
  14.     };
  15.     Variant(int i){
  16.         m_type = INT;
  17.         m_int = i;
  18.     }
  19.     Variant(float f){
  20.         m_type = FLOAT;
  21.         m_float = f;
  22.     }
  23.     Variant(const string &s){
  24.         m_type = STRING;
  25.         m_string = s;
  26.     }
  27.  
  28.     Type m_type;
  29.     int m_int;
  30.     float m_float;
  31.     string m_string;
  32. };
  33.  
  34. class ArgList{
  35. public:
  36.     template<class T>
  37.     ArgList(const T &val){
  38.         m_args.emplace_back(val);
  39.     }
  40.     template<class HEAD, class... TAIL>
  41.     ArgList(const HEAD &head,const TAIL&... tail){
  42.         m_args.emplace_back(head);
  43.         ArgList t(tail...);
  44.         m_args.insert(m_args.end(),t.m_args.begin(),t.m_args.end());
  45.     }
  46.  
  47.     vector<Variant> m_args;
  48. };
  49.  
  50. class ICommand{
  51. public:  
  52.     virtual void execute(const ArgList& args) = 0;
  53.     template<class... ARGS>
  54.     void executeList(const ARGS &... args){
  55.         execute(ArgList(args...));
  56.     }
  57. };
  58.  
  59. class Add : public ICommand{
  60. public:
  61.     virtual void execute(const ArgList& args){
  62.         assert(args.m_args.size() == 2);
  63.         assert(args.m_args[0].m_type == Variant::INT);
  64.         assert(args.m_args[1].m_type == Variant::INT);
  65.         cout << "Add result:" << args.m_args[0].m_int + args.m_args[1].m_int << endl;
  66.     }
  67. };
  68. class Negate : public ICommand{
  69. public:
  70.     virtual void execute(const ArgList& args){
  71.         assert(args.m_args.size() == 1);
  72.         assert(args.m_args[0].m_type == Variant::INT);
  73.         cout << "Negate result:" << -args.m_args[0].m_int<< endl;
  74.     }
  75. };
  76.  
  77. class Print : public ICommand{
  78.     virtual void execute(const ArgList& args){
  79.         for(auto &var : args.m_args){
  80.             switch(var.m_type){
  81.                 case Variant::INT:
  82.                     cout << "int " << var.m_int << ",";
  83.                     break;
  84.                 case Variant::FLOAT:
  85.                     cout << "float " << var.m_float << ",";
  86.                     break;
  87.                 case Variant::STRING:
  88.                     cout << "string " << var.m_string << ",";
  89.                     break;   
  90.             }
  91.         }
  92.         cout << endl;
  93.     }
  94. };
  95. int main(){
  96.     map<string,ICommand*> commands;
  97.     commands["Add"] = new Add();
  98.     commands["Negate"] = new Negate();
  99.     commands["Print"] = new Print();
  100.  
  101.     commands["Add"]->executeList(1,2);
  102.     commands["Negate"]->executeList(4);
  103.     commands["Print"]->executeList(1,2.0f,"helloworld!");
  104. }
Success #stdin #stdout 0s 3440KB
comments (?)
stdin
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Standard input is empty
stdout
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Add result:3
Negate result:-4
int 1,float 2,string helloworld!,
https://ideone.com/lhmjE0
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
public

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