策略模式与简单工厂的C++实现

最新推荐文章于 2026-01-07 11:46:22 发布

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#c++ #class #算法

本文介绍了一种使用策略模式实现的现金收费系统。通过不同的收费策略类（正常收费、打折收费、返利收费），系统能够灵活地应对各种收费场景。文章提供了具体的代码实现，并展示了如何根据用户选择调用相应的策略。

在之前先说明下，策略模式定义了一系列算法的方法，策略模式简化了简单工厂，让客户端只需一个类CONTEXT就可以了

//Factory.h #ifndef AFX_CLASS_CASHSUPER #define AFX_CLASS_CASHSUPER class CashSuper { public: virtual double acceptCash( double money) { return 0; } }; #endif #ifndef AFX_CLASS_CASH #define AFX_CLASS_CASH //正常收费 class CashNormal:public CashSuper { public: double acceptCash( double money ) { return money; } }; //打折收费 class CashRebate:public CashSuper { public: CashRebate( double moneyRebate ) { this->moneyRebate = moneyRebate; } double acceptCash( double money ) { return money * moneyRebate; } private: double moneyRebate; }; //返利收费 class CashReturn:public CashSuper { public: CashReturn( double moneyCondition , double moneyReturn ) { this->moneyCondition = moneyCondition; this->moneyReturn = moneyReturn; } double acceptCash( double money ) { double result = money; if( money >= moneyCondition ) { result = money - ( money / moneyCondition ) * moneyReturn; } return result; } private: double moneyCondition; double moneyReturn; }; #endif //策略CashContext #ifndef AFX_CLASS_CASHCONTEXT #define AFX_CLASS_CASHCONTEXT class CashContext { public: CashContext( int type ) { switch( type ) { case 0: cs = new CashNormal(); break; case 1: cs = new CashReturn( 300 , 100 ); break; case 2: cs = new CashRebate( 0.8 ); break; } } double GetResult( double money ) { return cs->acceptCash( money ); } private: CashSuper *cs; }; #endif

这里是实现

void CFactoryContextDlg::OnBnClickedBtnok() { // TODO: 在此添加控件通知处理程序代码 int type = m_computeCmb.GetCurSel(); CashContext *csuper = new CashContext( type ); double totalPrices = 0 ; CString itemstr1; GetDlgItem(IDC_EDTPRICE)->GetWindowText( itemstr1 ); int price =_tstoi( itemstr1); CString itemstr2; GetDlgItem(IDC_EDTNUM)->GetWindowText( itemstr2 ); int num = _tstoi( itemstr2 ); totalPrices = csuper->GetResult( price * num ); m_resultList.AddString(_T("单价：") + itemstr1 + _T(" 数量:") + itemstr2 ); str.Format(_T("%f"),totalPrices); CFont font; font.CreateFontW(20,20,0.1,0.1,FW_BOLD,false,true,false,true,false,true,true,true,_T("宋体")); CRect rect1; GetDlgItem(IDC_STATOTAL)->GetWindowRect(&rect1); CClientDC dc1(this); CFont* def_font = dc1.SelectObject(&font); ScreenToClient(&rect1); dc1.TextOut(rect1.left,rect1.bottom ,str, str.GetLength()+1); dc1.SelectObject(def_font); font.DeleteObject(); }