量化交易之设计模式篇 - 策略模式升级版

//
// Created by win10 on 2021/11/16.
//

#include <thread>
#include <iostream>
using namespace std;

// 策略基类
class COperation {
public:
    COperation() = default;
    virtual ~COperation() = default;

    virtual double getResult() = 0;

protected:
    int m_first;
    int m_second;
};

// 策略具体类
class AddOperation: public COperation {
public:
    AddOperation(int first, int second) {
        this->m_first = first;
        this->m_second = second;
    };
    virtual ~AddOperation() = default;

    virtual double getResult() override {
        return this->m_first + this->m_second;
    }
};

class SubOperation: public COperation {
public:
    SubOperation(int first, int second) {
        this->m_first = first;
        this->m_second = second;
    }
    virtual ~SubOperation() = default;

    virtual double getResult() override  {
        return this->m_first - this->m_second;
    }
};

class MultiOperation: public COperation {
public:
    MultiOperation(int first, int second) {
        this->m_first = first;
        this->m_second = second;
    }
    virtual ~MultiOperation() = default;

    virtual double getResult() override  {
        return this->m_first * this->m_second;
    }
};

class Context {
public:
    Context(int firstValue, int secondValue, char operationType) {

        switch (operationType) {
            case '+': {
                this->m_operationFunctionObj = new AddOperation(firstValue, secondValue);
                break;
            }
            case '-': {
                this->m_operationFunctionObj = new SubOperation(firstValue, secondValue);
                break;
            }
            case '*': {
                this->m_operationFunctionObj = new MultiOperation(firstValue, secondValue);
                break;
            }
            default:
                throw std::exception(string(string("Bad operationType: ") + operationType).c_str());

        }

    }

    double getResult() {
        return this->m_operationFunctionObj->getResult();
    }

    virtual ~Context() {
        if (this->m_operationFunctionObj != nullptr) {
            delete this->m_operationFunctionObj;
            this->m_operationFunctionObj = nullptr;
        }
    }

private:
    COperation* m_operationFunctionObj;
};

int main() {
    Context* context = new Context(10, 5, '*');
    std::cout << context->getResult() << std::endl;

    delete context;

    return 0;
}