Let’s go through Conversion Constructor and Conversion Operator in C++, with clear theory and examples:

📘 Conversion Constructor

➔ Definition:

A conversion constructor is a constructor that can be called with a single argument.

It converts one type into another by constructing an object of a class.

➔ Syntax:

class ClassName {
public:
    ClassName(Type arg); // Single-argument constructor
};

➔ Example:

#include<iostream>
using namespace std;

class Complex {
    double real, imag;
public:
    // Conversion constructor: int → Complex
    Complex(int r) {
        real = r;
        imag = 0;
    }
    void display() {
        cout << real << " + " << imag << "i" << endl;
    }
};

int main() {
    Complex c = 5;  // Implicit call: int → Complex
    c.display();    // Output: 5 + 0i
}

➔ Key Points:

• Converts a non-class type (like int, float) to a class type.
• Can cause implicit conversions, which sometimes is dangerous.
• To avoid accidental implicit conversion, you can use explicit keyword.

➔ With explicit: