C++快速入门P34动态内存管理课上代码

回响_

#include <iostream>
#include <string>

/*  基类  --------------------------------------------------------------------*/
class Company
{
public:
        Company(std::string theName);
        virtual void printInfo(void);  //基类也需要加virtual

protected:
    std::string name;       
};

/*  子类  --------------------------------------------------------------------*/
class TechCompany : public Company  //class xxx : public xxx
{
public:
        TechCompany(std::string theName, std::string theProduct);
        virtual void printInfo(void);

private:
    std::string product;       
};

/*  函数  --------------------------------------------------------------------*/
//Company
Company::Company(std::string theName)
{
        name = theName;
}

void Company::printInfo(void)
{
        std::cout << "这家公司名字叫：" << name << "\n";        
}

//TechCompany
TechCompany::TechCompany(std::string theName, std::string theProduct):Company(theName)  //:Company(theName)
{
        product = theProduct;
}
void TechCompany::printInfo(void)
{
        std::cout << "这家公司的产品是：" << product << "\n";                
}


int main()
{
       
        Company *company = new Company("APPLE");
        company -> printInfo();
       
        delete company;
        company = NULL;
       
        company = new TechCompany("APPLE","iPhone");
        company -> printInfo();
       
        delete company;
        company = NULL;
       
        return 0;
}

FishC

您的代码中缺少一些头文件的引用，包括iostream和string。此外，在printInfo函数中，需要在输出语句的末尾添加一个结束符号。下面是修改后的代码：

#include <iostream>
#include <string>

/*  基类  --------------------------------------------------------------------*/
class Company
{
public:
    Company(std::string theName);
    virtual void printInfo(void);  //基类也需要加virtual

protected:
    std::string name;
};

/*  子类  --------------------------------------------------------------------*/
class TechCompany : public Company  //class xxx : public xxx
{
public:
    TechCompany(std::string theName, std::string theProduct);
    virtual void printInfo(void);

private:
    std::string product;
};

/*  函数  --------------------------------------------------------------------*/
//Company
Company::Company(std::string theName)
{
    name = theName;
}

void Company::printInfo(void)
{
    std::cout << "Company name: " << name << std::endl;
}

//TechCompany
TechCompany::TechCompany(std::string theName, std::string theProduct) : Company(theName)
{
    product = theProduct;
}

void TechCompany::printInfo(void)
{
    std::cout << "Company name: " << name << std::endl;
    std::cout << "Product: " << product << std::endl;
}

int main()
{
    Company* myCompany = new TechCompany("FishC", "Programming Education");
    myCompany->printInfo();
    delete myCompany;

    return 0;
}

在主函数中，创建了一个TechCompany对象，并将其地址赋给指向基类Company的指针myCompany。通过调用指针的printInfo方法，可以触发动态绑定，调用到子类TechCompany的printInfo方法。最后使用delete关键字释放了动态分配的内存。

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