Important Points about Operator Overloading

Why can’t the above-stated operators be overloaded?

1) For operator overloading to work, at least one of the operands must be a user-defined class object.

2) Assignment Operator: Compiler automatically creates a default assignment operator with every class. The default assignment operator does assign all members of the right side to the left side and works fine in most cases (this behavior is the same as the copy constructor). See this for more details.

3) Conversion Operator: We can also write conversion operators that can be used to convert one type to another type.

Example:

C++

// C++ Program to Demonstrate the working
// of conversion operator
#include <iostream>
using namespace std;
class Fraction {
private:
    int num, den;
 
public:
    Fraction(int n, int d)
    {
        num = n;
        den = d;
    }
 
    // Conversion operator: return float value of fraction
    operator float() const
    {
        return float(num) / float(den);
    }
};
 
int main()
{
    Fraction f(2, 5);
    float val = f;
    cout << val << '\n';
    return 0;
}

Output

0.4

Overloaded conversion operators must be a member method. Other operators can either be the member method or the global method.

4) Any constructor that can be called with a single argument works as a conversion constructor, which means it can also be used for implicit conversion to the class being constructed.

Example:

C++

// C++ program to demonstrate can also be used for implicit
// conversion to the class being constructed
#include <iostream>
using namespace std;
 
class Point {
private:
    int x, y;
 
public:
    Point(int i = 0, int j = 0)
    {
        x = i;
        y = j;
    }
    void print()
    {
        cout << "x = " << x << ", y = " << y << '\n';
    }
};
 
int main()
{
    Point t(20, 20);
    t.print();
    t = 30; // Member x of t becomes 30
    t.print();
    return 0;
}

Output

x = 20, y = 20
x = 30, y = 0

Quiz on Operator Overloading

Operator Overloading in C++

in C++, Operator overloading is a compile-time polymorphism. It is an idea of giving special meaning to an existing operator in C++ without changing its original meaning.

In this article, we will further discuss about operator overloading in C++ with examples and see which operators we can or cannot overload in C++.

Important Points about Operator Overloading

C++

C++

Operator Overloading in C++

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