试图从另一个C ++类返回一个类对象

Question

Hello I've been trying to return an object from a class but for some reason, whenever I try to return it, it fails but all other surrounding code works perfectly.

emp.h

class drvr{
private:
    string title;
    string empname;
public:
    drvr(string titlez, string name){
    title = titlez;
    empname = name;
    }

node.h

class node{
private:
    drvr edata(string, string);
    node * next;
public:
    node(emp rec){
       edata(rec);
       next = NULL;
    }
   drvr getData(){
   return edata;
   }

I get the error:

cannot convert 'node::data' from type 'drve (node::)(int, std::__cxx11::string) {aka drvr (node::)(int, std::__cxx11::basic_string)}' to type 'drvr'|

Answer 1

You are declaring edata as a member function of class node that takes two arguments of type std::string and returns drvr object , but inside getData you are returning the address of that function , so the compiler tells you that the type of the object you are returning does not much what it expects this method to be returning as a type , obviously that's not what you want to do . i can see from the code that you are coding a linked-list , so edata should be of type drvr and it should be defined like this : drvr edata;

And for setting a value for that attribute you can add a method to node :

void setEdata(const drvr & d )
{
this->edata = d;
}

or

void setEdata(const std::string & title,const std::string & empname )
    {
    this->edata = drvr(title,empname);
    }

Answer 2

When you say drvr edata(string, string); you are actually declaring a function named edata that returns a drvr and takes two string .

To make it a variable initialized with string use {} .

drvr edata{"hello", "world"};

Answer 3

Use like this:

class drvr {
private:
    string title;
    string empname;
public:
    drvr(string titlez, string name) {
        title = titlez;
        empname = name;
    }
    drvr(const drvr& other)
    {
        title = other.title;
        empname = other.empname;
    }

};    

class node {    
private:
    drvr edata;
    node * next;
public:
    node(const drvr& rec)
        :edata(rec)
    {
        next = nullptr;
    }

    drvr getData()
    {
        return edata;
    }
};