Why Doesn't `Class object();` Create a C Object?

Understanding the Absence of Constructor Invocation

In C , constructors are used to initialize objects of a class. However, in the provided code snippet, the constructor is not being invoked, resulting in unexpected behavior.

The Problem

The problematic line:

Class object();

does not actually invoke the constructor for the Class class. Instead, it declares a function returning a Class object. To correctly call the constructor and create an object, a semicolon (;) must be appended to the line:

Class object;

Behind the Scenes: The Most Vexing Parse

The initial code snippet highlights an issue known as the "most vexing parse" in C . When encountering the line:

Class object();

the C parser ambiguously interprets it as either a function declaration or a function call with an empty argument list. This ambiguity often leads to confusion and unexpected results.

Correcting the Code

To invoke the constructor and create an object, the code should be updated to:

#include <iostream>
using namespace std;

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

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

int main() {
    Class object; // Correctly invokes the constructor
}

Run the corrected code to observe the expected output:

default constructor called
destructor called

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