How Do I Correctly Instantiate a C Class Object and Invoke Its Constructor?

Understanding Constructor Calls in C

In C , constructors are special member functions that automatically execute when objects of a class are created. They are responsible for initializing the object's data members.

The Problem

Consider the following code snippet:

#include <iostream>
using namespace std;

class Class {
    public:
        Class() {
            cout << "default constructor called" << endl;
        }

        ~Class() {
            cout << "destructor called" << endl;
        }
};

int main() {
    Class object(); // Incorrect syntax
}

The main() function attempts to create an object of class Class. However, it does not call the constructor as expected.

The Cause

The issue lies in the incorrect syntax used in the object declaration:

Class object();

This line declares a function named object() that returns a Class object. To correctly create an object of class Class, we should use the following syntax:

Class object;

The Solution

By removing the parentheses after the class name, we properly declare an object of class Class. This object will correctly call the default constructor, as expected.

Additional Notes

• The most vexing parse is a phenomenon in C where code can be interpreted as either a function declaration or a class declaration depending on the context.
• To avoid this ambiguity, it is recommended to follow the rule of thumb: "Always put parentheses after a class name to indicate a constructor call."

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