Re: [問題] template一問

[legnaleurc (CA)]

※ 引述《NIKE74731 (做遊戲的心)》之銘言：
: class Base
: {
: public: virtual void Run() = 0;
: };
: Base* Get( int iType )
: {
:     switch( iType )
:     {
:     case 1:
:         return new D1;
:         break;
:     case 2:
:         return new D2;
:         break;
:     case 3:
:         return new D3;
:         break;
:     }
: }

class Factory {
public:
    typedef std::function< Base *() > Creator;
    static Base * Create( int id );
    static bool Register( int id, Creator c );
private:
    static std::map< int, Creator > f_;
};

Base * Factory::Create( int id ) {
    std::map< int, Creator >::const_iterator it = f_.find( id );
    if( it == f_.end() ) {
        return NULL;
    }
    return it->second();
}

bool Register( int id, Creator c ) {
    if( f_.find( id ) != f_.end() ) {
        return false;
    }
    f_.insert( std::make_pair( id, c ) );
    return true;
}

// register
Factory::Register( 1, []() {
    return new D1;
} );
Factory::Register( 2, []() {
    return new D2;
} );
Factory::Register( 3, []() {
    return new D3;
} );

// create instance
int i;
std::cin >> i;
Base * obj = Factory::Create( i );


很陽春的 factory pattern

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