C2804 binary 'operator ==' has too many parameters

June 24, 2023

I am a beginner in programming I learn operator And i have a problem with operator== in Visul studio I get the error :C2804 binary ‘operator ==’ has too many parameters

Duree.cpp

#include "Duree.h"
#include<iostream>
Duree::Duree(int h,int m,int s) :
    m_h(h),m_m(m),m_s(s)
{

}


bool Duree::estEgal(Duree const& b) const {
    return (m_h == b.m_h && m_m == b.m_m && m_s == b.m_s);


}
bool operator==(Duree const& a, Duree const& b)
{
    return a.estEgal(b);
}

Duree.h

#ifndef DUREE_H_INCLUDED
#define DUREE_H_INCLUDED

class Duree
{
public:
    Duree(int h = 0,int m = 0,int s = 0);
 
    bool estEgal(Duree const& b) const;

    bool operator==(Duree const& a, Duree const& b);

private:
    int m_h;
    int m_m;
    int m_s;
};

#endif

main.cpp

#include <iostream>
#include "Duree.h"

using namespace std;

int main()
{
    Duree a(10,10,10),b(20,20,20);

    cout << "Hello world! " << endl;
    if (a == b) {
        cout << "a = b";
    }
    

    return 0;
}

Error C2804 binary ‘operator ==’ has too many parameters
Error C2676 binary ‘==’: ‘Duree’ does not define this operator or a conversion to a type acceptable to the predefined operator cplusplus
Error C2804 binary ‘operator ==’ has too many parameters cplusplus
Error (active) E0349 no operator "==" matches these operands cplusplus

Severity Code Description Project File Line Suppression State
Error C2804 binary ‘operator ==’ has too many parameters cplusplus C:\Users\ACER\source\repos\cplusplus\cplusplus\Duree.h 12
Error C2676 binary ‘==’: ‘Duree’ does not define this operator or a conversion to a type acceptable to the predefined operator cplusplus C:\Users\ACER\source\repos\cplusplus\cplusplus\cplusplus.cpp 11
Error C2804 binary ‘operator ==’ has too many parameters cplusplus C:\Users\ACER\source\repos\cplusplus\cplusplus\Duree.h 12
Error (active) E0349 no operator "==" matches these operands cplusplus C:\Users\ACER\source\repos\cplusplus\cplusplus\cplusplus.cpp 11

>Solution :

If you define the operator as non-static member function, there is one additional "hidden parameter": this.

For this reason operators implemented as non-static member functions must take only a single parameter: The second operand of the operator.

class Duree
{
public:
    Duree(int h = 0, int m = 0, int s = 0);

    bool operator==(Duree const& b) const
    {
        return (m_h == b.m_h && m_m == b.m_m && m_s == b.m_s);
    }

private:
    int m_h;
    int m_m;
    int m_s;
};

...

Duree a;
Duree b;

//the following 2 rhs expressions are the same
bool b1 = (a == b); 
bool b2 = a.operator==(b);

You could also add the implement an operator at namespace scope inside the class body by making the operator a friend:

class Duree
{
public:
    Duree(int h = 0, int m = 0, int s = 0);

    friend bool operator==(Duree const& a, Duree const& b)
    {
        return (a.m_h == b.m_h && a.m_m == b.m_m && a.m_s == b.m_s);
    }

private:
    int m_h;
    int m_m;
    int m_s;
};

// the operator definition above basically has the same effect as defining
//
// inline bool operator==(Duree const& a, Duree const& b)
//
// here + adding it as a friend of the Duree class