C++ concept guides

Build a mental model before your next puzzle. Learn references, pointers, object lifetime, data structures and algorithms through code examples, common mistakes and short interactive checks.

• Fundamentals · Getting started

  C++ first steps

  Start with names, stored numbers and reading one instruction at a time.

• Functions · Getting started

  Functions and copies

  Follow a function call, its separate input number and the result it sends back.

• Functions · Language foundations

  References

  Another name for an object. Follow what changes in the caller.

• Pointers · Memory & ownership

  Pointers

  Separate an address from the object it leads to.

• Memory · Memory & ownership

  RAII & resource lifetime

  Make cleanup part of an object’s lifetime.

• Memory · Memory & ownership

  Stack vs heap

  Separate where an owner lives from how long its object lives.

• OOP · Objects & interfaces

  Inheritance

  Reuse a shared interface and behavior while keeping the relationship honest.

• OOP · Objects & interfaces

  Polymorphism

  One interface can call behavior supplied by different object types.

• OOP · Objects & interfaces

  Virtual functions

  Separate dynamic dispatch from the compiler’s override check.

• Data Structures · Data structures

  Linked lists

  Follow links, reason about reachability, and separate unlinking from deletion.

• Data Structures · Data structures

  Stacks & queues

  Choose what leaves next: the newest item or the oldest.

• STL · Data structures

  Vectors

  Distinguish existing elements, spare storage, and invalidated addresses.

• Functions · Algorithms & reasoning

  Recursion

  Follow smaller calls down and returned answers back up.

• Big-O · Algorithms & reasoning

  Big O & growth

  Count growing work, then compare how it scales with input size.