Object lifecycle in C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are the main stages of an object's lifecycle in C++?

The main stages are: creation (when the object is made), usage (when the object is used), and destruction (when the object is removed and its memory freed).

beginner

What happens during the construction of an object?

During construction, the object's memory is allocated and its constructor function runs to set up initial values or states.

beginner

What is the role of a destructor in C++?

A destructor is a special function that runs automatically when an object is destroyed. It cleans up resources like memory or files the object used.

intermediate

How does scope affect an object's lifecycle?

An object created inside a scope (like inside a function) is destroyed automatically when the scope ends, meaning its destructor is called then.

intermediate

What is the difference between automatic and dynamic object lifecycles?

Automatic objects are created and destroyed automatically based on scope. Dynamic objects are created with new and must be manually destroyed with delete.

When is an object's destructor called in C++?

A Only when the program ends

B When the object is created

C When the program starts

D When the object goes out of scope or is deleted

The destructor runs when the object is no longer needed, either when it goes out of scope or when deleted if created dynamically.

Which keyword is used to create a dynamic object in C++?

A new

B create

C malloc

D construct

The new keyword allocates memory and calls the constructor for dynamic objects.

What happens if you forget to delete a dynamic object?

A Program crashes immediately

B Object is destroyed automatically

C Memory leak occurs

D Destructor runs twice

Not deleting dynamic objects causes memory to stay allocated, leading to memory leaks.

Which function is automatically called when an object is created?

A Copy

B Constructor

C Main

D Destructor

The constructor sets up the object when it is created.

If an object is declared inside a function, when is it destroyed?

A When the function ends

B At program start

C When the object is used

D Never

Objects declared inside a function are destroyed when the function finishes and the scope ends.

Explain the lifecycle of an object in C++ from creation to destruction.

Think about what happens when you make an object and when it disappears.

Describe the difference between automatic and dynamic object lifecycles in C++.

Consider how and when objects are created and destroyed.