Skip to content

Latest commit

 

History

History
91 lines (56 loc) · 1.82 KB

CppMagicConstant.md

File metadata and controls

91 lines (56 loc) · 1.82 KB
Raw

 

 

 

 

 

(C++) magic constant

 

A magic constant is the use of a literal without mentioning where that literal came from.

 

For example, in the code below, 12 is a magic constant that occurs twice. How is this 12 determined? Is it the number of notes per chord, or is it a dozen? And if the upper 12 is changed, must the lower 12 be changed as well?

 

int main() {   for (int i=0; i!=12; ++i)   {     //   }   for (int i=0; i!=12; ++i)   {     //   } }

 

 

 

 

 

Advice

 

 

 

 

 

 

References

 

  1. Bjarne Stroustrup. The C++ Programming Language (4th edition). 2013. ISBN: 978-0-321-56384-2. Chapter 6.6. Advice. page 169: '[6] Avoid "magic constants"'
  2. Bjarne Stroustrup. The C++ Programming Language (4th edition). 2013. ISBN: 978-0-321-56384-2. Chapter 10.6. Advice. page 271: '[6] Define symbolic constants to avoid "magic constants"'
  3. Herb Sutter, Andrei Alexandrescu. C++ coding standards: 101 rules, guidelines, and best practices. 2005. ISBN: 0-32-111358-6. Item 17: 'Avoid magic numbers'