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Advanced 18 min readModule: Module 6: Classes, Constructors & Destructors

Classes, Initializer Lists & Destructors

Design efficient C++ classes using member initializer lists, rule of zero, and const correctness.

What You Will Learn in This Lesson

  • Member initializer list syntax (: member(val)) for direct construction
  • Class Destructors (~Class()) for resource cleanup
  • Const member methods (void getInfo() const) preventing accidental mutations

Introduction & Core Concept

Classes in C++ encapsulate data members and member functions. Initializer lists initialize members directly before the constructor body executes.
WHY DOES THIS MATTER IN THE REAL WORLD?

Initializing members in initializer lists avoids constructing default objects only to overwrite them inside the constructor body.

C++ Class with Initializer List

cpp
cpp
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#include <iostream>
#include <string>
 
class Engine {
private:
    std::string name;
    int horsepower;
public:
    Engine(std::string n, int hp) : name(std::move(n)), horsepower(hp) {}
    int getHP() const { return horsepower; }
};
 
int main() {
    Engine v8("V8 Twin Turbo", 650);
    std::cout << "Horsepower: " << v8.getHP() << " HP" << std::endl;
    return 0;
}

Line-by-Line Technical Breakdown

1Methods marked 'const' can be safely called on const instances of the class.

Try It Yourself (Interactive Editor)

Modify the code in real-time and click Run to test live browser output and console logs.

Intelligent Code Runner & Live Sandbox[CPP]
CPP SOURCE EDITOR
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Industry Best Practices & Professional Standards

  • Always use member initializer lists instead of assignments inside constructor bodies.

Lesson Summary & Core Takeaways

  • Initializer lists and const correctness produce efficient, predictable C++ classes.