CODEWITHSUNDEEP
c++
sn710
sn710

Reputation: 611

Use of operator overloading in structure within class

I have a header file where i am declaring a class with a structure within it. Also i am declaring an overloading operator(!=, to compare structures) as member of this class. I am giving the definition of this operator in the cpp file. But i am not able to access the members of the structure

car.h

class car
{ 
int carsor;

struct model
{
    int id;

    int mode;

}prev,curr;

bool operator !=(const model& model1);

};

car.cpp

#include "car.h"

bool car::operator !=(const model& model1)
{
if((model1.id==model.id)&&(model1.mode==model.mode))
{
    return false;
}

else
{

    return false;
}
}

The error i get is this 

Error   2   error C2275: 'car::model' : illegal use of this type as an expression

how should i access the the structure members?

Upvotes: 0

Views: 284

Answers (2)

Useless
Useless

Reputation: 67772

This:

bool car::operator !=(const model& model1)
{

is a method comparing a car to a model. This, however:

bool car::model::operator != (car::model const &other) const
{
  return !(*this == other);
}

is a method comparing two models (I've written it here as a method of car::model, but it could be a free function if you prefer.

I've also written it in terms of operator==, because the logic almost always works out easier:

bool car::model::operator ==(car::model const &other) const
{
    return (this->id == other.id) && (this->mode == other.mode);
}

These methods would be declared as:

class car
{ 
    struct model
    {
        int id;
        int mode;
        bool operator==(model const&) const;
        bool operator!=(model const&) const;
        // ...

Upvotes: 0

SomeWittyUsername
SomeWittyUsername

Reputation: 18368

if((model1.id==model.id)&&(model1.mode==model.mode)) - model is the name of your class and not your object. Your object is accessible via this or you may omit it altogether inside the class. Use if((model1.id==prev.id)&&(model1.mode==prev.mode)) to compare with prev or if((model1.id==next.id)&&(model1.mode==next.mode)) to compare with next.

Upvotes: 3

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