C++17 Quick Syntax Reference: A Pocket Guide to the Language, APIs and Library

© Mikael Olsson 2018

Mikael OlssonC++17 Quick Syntax Referencehttps://doi.org/10.1007/978-1-4842-3600-0_23

23. Constants

Mikael Olsson¹ 

(1)

Hammarland, Finland

 

A constant is a variable that has a value that cannot be changed once the constant has been assigned. This allows the compiler to enforce that the variable’s value is not changed anywhere in the code by mistake.

Constant Variables

A variable can be made into a constant by adding the const keyword either before or after the data type. This modifier means that the variable becomes read-only, and it must therefore be assigned a value at the same time as it is declared. Attempting to change the value anywhere else results in a compile-time error.

const int var = 5;

int const var2 = 10; // alternative ...