411 REFERENCE · Wikibooks
C++ Language/Type/Shortcuts/FromInitialization
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
The compiler can infer a variable's type from its initialization data.
So defining auto iVar = 11; is the same as defining int iVar = 11; (because 11 is a int literal).
Additional information about inferring type from initialization data (includes interactive examples)