base-class

问题 This question already has answers here : C++ inheritance - inaccessible base? (2 answers) Closed 3 years ago . I define a class B1 and a derived class D1 at first. Then I want to define a reference to B1 and initialize that to the D1 object I just defined. Here comes the error, saying that "conversion to inaccessible base class 'B1' is not allowed", which I don't know why. #include "std_lib_facilities.h" class B1 { public: virtual void vf() { cout << "B1::vf()\n"; }; void f() { cout << "B1::f

问题 This question already has answers here : C++ inheritance - inaccessible base? (2 answers) Closed 3 years ago . I define a class B1 and a derived class D1 at first. Then I want to define a reference to B1 and initialize that to the D1 object I just defined. Here comes the error, saying that "conversion to inaccessible base class 'B1' is not allowed", which I don't know why. #include "std_lib_facilities.h" class B1 { public: virtual void vf() { cout << "B1::vf()\n"; }; void f() { cout << "B1::f

问题 This question already has answers here : C++ inheritance - inaccessible base? (2 answers) Closed 3 years ago . I define a class B1 and a derived class D1 at first. Then I want to define a reference to B1 and initialize that to the D1 object I just defined. Here comes the error, saying that "conversion to inaccessible base class 'B1' is not allowed", which I don't know why. #include "std_lib_facilities.h" class B1 { public: virtual void vf() { cout << "B1::vf()\n"; }; void f() { cout << "B1::f

问题 This question already has answers here : C++ inheritance - inaccessible base? (2 answers) Closed 3 years ago . I define a class B1 and a derived class D1 at first. Then I want to define a reference to B1 and initialize that to the D1 object I just defined. Here comes the error, saying that "conversion to inaccessible base class 'B1' is not allowed", which I don't know why. #include "std_lib_facilities.h" class B1 { public: virtual void vf() { cout << "B1::vf()\n"; }; void f() { cout << "B1::f

问题 I'd like to make a class that extends the int base class, so that the object itself is an integer (i.e. you set it and read from it directly), but also has input validation - for example, only allow a given range. From what I have researched, the __init__ method is not called when you extend normal base classes, so I'm not sure how to do this. I'm also not clear on how you access the value of the object (i.e. the actual integer assigned to it) or modify that value from within the class. I see

问题 I'd like to make a class that extends the int base class, so that the object itself is an integer (i.e. you set it and read from it directly), but also has input validation - for example, only allow a given range. From what I have researched, the __init__ method is not called when you extend normal base classes, so I'm not sure how to do this. I'm also not clear on how you access the value of the object (i.e. the actual integer assigned to it) or modify that value from within the class. I see

问题 I believe Constructors and Destructors in base class cannot be inherited by derived classes of the base class. Is my understanding correct. 回答1: Your understanding is correct. For example, if you have class Base { Base(int i) {} }; class Derived: public Base {}; Derived d(3); This will not compile because the Base constructor is not inherited. Note that default and copy constructor are created by the compiler if possible, and call the corresponding constructor of base classes, therefore for

问题 My question is what is the reason to write Super.toString() in base class and what it returns and why ? this is my code : class Person { public String toString() { return super.toString() /*+ "->" + "Person" + name + "------"*/; } } what is supposed to be return ? and thanks i m beginner in java 回答1: Your class Person should extend parent class where you define method toString(), otherwise your parent class is class Object and the native method of this class is going to be used: public String

问题 I was under impression that it's impossible, see for example: Calling the constructor of the base class after some other instructions in C++ But the following program runs and produces two lines of "Constructor Person": #include <iostream> class Person { public: Person() { std::cout << "Constructor Person" << std::endl; } }; class Child : public Person { public: Child() { c = 1; Person(); } int c; }; int main() { Child child; return 0; } The first one is implicit call of the default

问题 I have base class which is serialized. [ProtoContract] public class Web2PdfEntity { [ProtoMember(1)] public string Title { get; set; } [ProtoMember(2)] public string CUrl { get; set; } } I would like to deserialize Web2PdfEntity class to Web2PdfServer which is inherited from Web2PdfEntity. public class Web2PdfServer : Web2PdfEntity { public void MyServerMethod {} public void MyServerMethod2{} } I have tried to use code below to deserialize class, unfortunately the properties are not set. var