The C++ Concept Deck

A curated flashcard deck covering the most important C++ concepts, language mechanics, and interview-relevant theory.

What is C++?

• general purpose programming language that is biased towards system programming.

• supports object oriented programming (abstraction, encapsulation, inheritance, polymorphism)

• supports generic programming (reusable containers/algorithms)

• supports functional programming (programming paradigm based on the idea of building software by composing pure functions)

Why does C++ allow unsafe code?

• to access hardware directly (e.g. to treat an integer as a pointer to (address of) a device register)

• to achieve optimal run-time and space performance (e.g. unchecked access to elements of an array and unchecked access to an object through a pointer)

• to be compatible with C

What unsafe C++ code practices should be avoided unless absolutely necessary?

• don’t use casts

• keep C-style [] arrays out of interfaces

  • hide them in the innards of high-performance functions and classes where they are needed and write the rest of the program using proper strings, vectors, etc.

• avoid void*

  • keep them inside low-level functions and data structures if you really need them and present type safe interfaces, usually templates, to your users

• avoid unions

• if you have any doubts about the validity of a pointer, use a smart pointer instead

• don’t use “naked” new and delete

  • use containers, resource handles, etc., instead

• don’t use ...-style variadic functions (“printf style”)

• avoid macros except for #include guards

Why are some things left undefined in C++?

C++ is meant to exploit hardware directly and efficiently. C++ is meant deal with hardware entities (bytes, bits, words, addresses) they way they are provided on the machine.