Initialization in C++ is bonkers (2017)

a year ago

C++ initialization rules are complex and can lead to undefined behavior if not handled carefully.
Three main types of initialization in C++: default-, value-, and zero-initialization, each with specific rules.
Default-initialization calls the default constructor for classes, leaves scalar types uninitialized (indeterminate values).
Value-initialization may involve zero-initialization first, especially for classes with non-user-provided default constructors.
Zero-initialization sets scalar types to 0, class members to zero, and is applied to static/thread-local variables before other initializations.
User-provided constructors affect initialization behavior; defaulting a constructor at declaration vs. definition changes its classification.
Value-initialization of a class with a non-user-provided default constructor includes zero-initialization, ensuring members start as 0.
Reading uninitialized variables is undefined behavior, emphasizing the importance of explicit initialization.
C++ offers 18 forms of initialization, highlighting the language's complexity in this area.
Best practice: always initialize variables to avoid undefined behavior and ensure predictable program execution.

Hasty Briefsbeta