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Nono34
Asked: 2022-10-22 09:41:23 +0800 CST 2022-10-22 09:41:23 +0800 CST

Why the error with my inheritance?

  • 772

Doing a job of assigning names , age , code and note when I try to assign an inheritance to then a setwith AlumnoH, I get an error. I think it may be the way I'm inheriting it but I really don't have much idea, the error says that a '{'(yes, sorry, this error was given to me in the void line StudentH::setValue2(string _name, int _age , string _codigo, float _notafinal) : Person(_name, _age){}, right where it says : Person(_name, _age), exactly in the ':') so that it is correct, but I don't think that is the problem. In an example I saw they didn't need that.

If you could recommend me something to review that part, it would be more than great. Thank you!

inheritance.CPP

#include <iostream>
#include <string>
#include "herencia.h"
using namespace std;


Persona::Persona(){}

void Persona::setValue(string _name, int _age){
    this-> name = _name;
    this-> age = _age;
}
const string Persona::getName() const{
    return name;
}
const int Persona::getAge() const{
    return age;
}

void AlumnoH::setValue2(string _name, int _age, string _codigo, float _notafinal) : Persona(_name, _age){
    this-> codigo = _codigo;
    this-> notafinal = _notafinal;
}


Persona::~Persona(){}

inheritance.h

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

class Persona{
private:
    string name;
    int age;
public:
    Persona();
    virtual ~Persona();
    Persona(string, int);
    virtual ~Persona();
    void setValue(string _name, int _age);
    const string getName() const;
    const int getAge() const;
};

class AlumnoH : public Persona{
private: 
    string codigo;
    float notafinal;
public:
    AlumnoH();
    virtual ~AlumnoH();
    
    void setValue2(string, int, string, float) : Persona(string, int);
    const string getName() const;
    const int getAge() const;
    const string getCodigo() const;
    const float getNotafinal() const;
};

main.cpp

#include <iostream>
#include "herencia.h"
using namespace std;

template<typename T>

void print(T objeto){
    cout << objeto.getName() << endl;
    cout << objeto.getAge() << endl;
}


int main(){
    Persona P1;
    P1.setValue("Hernan", 12);
    print(P1);
}
c++

2 Answers

  1. Based on the information from this compiler :

    • You are declaring the destructor 2 times:

      virtual ~Persona();

    • You can delegate constructors but not functions. What you can do is call parent functions like so:

      void AlumnoH::setValue2(string _name, int _age, string _codigo, float _notafinal){
    Persona::setValue(_name, _age); // <---
    this-> codigo = _codigo;
    this-> notafinal = _notafinal;
}

      Also, there is no constructor Persona(string, int).

    • Delegating a function is an implementation detail. So you should not write the delegation as part of the declaration. For example, you add a constructor to Persona:

      // Declaración
Persona(string, int);

// Definición
Persona(string, int) : Persona() {
   ...
}

      In fact, since the declaration only needs a name, parameters, and return type, if you write it like:

      Persona(string, int) : Persona();

      The compiler interprets that you are giving a definition. That's why he says expected '{' or ','. Because it expects the body of the function.

    The file herencia.hwould look like this:

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

class Persona{
private:
    string name;
    int age;
public:
    Persona();
    virtual ~Persona();
    Persona(string, int);
    void setValue(string _name, int _age);
    const string getName() const;
    const int getAge() const;
};

class AlumnoH : public Persona{
private: 
    string codigo;
    float notafinal;
public:
    AlumnoH();
    virtual ~AlumnoH();
    
    void setValue2(string, int, string, float);
    const string getName() const;
    const int getAge() const;
    const string getCodigo() const;
    const float getNotafinal() const;
};
    • 0
  2. Best Answer

    The error is that you do an inheritance in the method:

    void setValue(string _name, int _age);

    This receives parameters, but ideally it would be to send those parameters to the constructor directly;

    Persona::Persona(){}

    I see that you have the empty person constructor and you are inheriting the person constructor to a method, which causes the inheritance error, the ideal would be the following:

    #include <iostream>
#include <string>
#include "herencia.h"
using namespace std;


Persona::Persona(string _name,int _age){
    this-> name = _name;
    this-> age = _age;
}

const string Persona::getName() const{
    return name;
}
const int Persona::getAge() const{
    return age;
}

vAlumnoH::vAlumnoH(string _name, int _age, string _codigo, float 
 _notafinal) : Persona(_name, _age){
    this-> codigo = _codigo;
    this-> notafinal = _notafinal;
}


Persona::~Persona(){}

    It is the most recommended thing to do

    • 0