C++快速入门P34动态内存管理课上代码

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#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：

1. #include <iostream>
   
2. #include <string>
   
3. 
   
4. /*  基类  --------------------------------------------------------------------*/
   
5. class Company
   
6. {
   
7. public:
   
8.     Company(std::string theName);
   
9.     virtual void printInfo(void);  //基类也需要加virtual
   
10. 
    
11. protected:
    
12.     std::string name;
    
13. };
    
14. 
    
15. /*  子类  --------------------------------------------------------------------*/
    
16. class TechCompany : public Company  //class xxx : public xxx
    
17. {
    
18. public:
    
19.     TechCompany(std::string theName, std::string theProduct);
    
20.     virtual void printInfo(void);
    
21. 
    
22. private:
    
23.     std::string product;
    
24. };
    
25. 
    
26. /*  函数  --------------------------------------------------------------------*/
    
27. //Company
    
28. Company::Company(std::string theName)
    
29. {
    
30.     name = theName;
    
31. }
    
32. 
    
33. void Company::printInfo(void)
    
34. {
    
35.     std::cout << "Company name: " << name << std::endl;
    
36. }
    
37. 
    
38. //TechCompany
    
39. TechCompany::TechCompany(std::string theName, std::string theProduct) : Company(theName)
    
40. {
    
41.     product = theProduct;
    
42. }
    
43. 
    
44. void TechCompany::printInfo(void)
    
45. {
    
46.     std::cout << "Company name: " << name << std::endl;
    
47.     std::cout << "Product: " << product << std::endl;
    
48. }
    
49. 
    
50. int main()
    
51. {
    
52.     Company* myCompany = new TechCompany("FishC", "Programming Education");
    
53.     myCompany->printInfo();
    
54.     delete myCompany;
    
55. 
    
56.     return 0;
    
57. }

复制代码

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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