量化交易之设计模式篇 - 简单工厂模式

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

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

/*
 * 简单工厂模式:
 * 核心思想是用一个工厂来 根据输入的条件产生不同的类，然后根据不同类的 virtual 函数得到不同的结果。
 */
class COperation {
public:
    COperation() = default;
    virtual ~COperation() = default;
    virtual double getResult() = 0;

public:
    int m_first{};
    int m_second{};
};

class AddOperation: public COperation {
public:
    double getResult() override {
        return this->m_first + this->m_second;
    }
    AddOperation() = default;
    ~AddOperation() = default;
};

class SubOperation: public COperation {
public:
    double getResult() override  {
        return this->m_first - this->m_second;
    }
    SubOperation() = default;
    ~SubOperation() = default;
};

class MultiOperation: public COperation {
public:
    double getResult() override  {
        return this->m_first * this->m_second;
    }
    MultiOperation() = default;
    ~MultiOperation() = default;
};

// 工厂类
class Factory {
public:
    static COperation* create(char operationType);
};
COperation *Factory::create(char operationType) {

    COperation* operation;
    switch (operationType) {
        case '+': {
            operation = new AddOperation();
            break;
        }
        case '-': {
            operation = new SubOperation();
            break;
        }
        case '*': {
            operation = new MultiOperation();
            break;
        }
        default: {
            throw std::exception((string("Bad operationType: ") + operationType).c_str());
        }
    }

    return operation;
}

int main() {

    COperation* operation = Factory::create('*');

    operation->m_first = 5;
    operation->m_second = 10;

    std::cout << "result: " << operation->getResult() << std::endl;

    delete operation;

    return 0;
}