what is bool(), int(), and double() in c++/c++11?

Question

what is bool(), int(), and double() in c++/c++11? Are they true, 0 and 0.0 in c++ or c++11 standard?

Actually it is `false`, `0` and `0.0` respectively. – Cory Kramer Dec 13 '14 at 21:33 — Cory Kramer, Dec 13 '14 at 21:33

score 3 · Accepted Answer · answered Dec 13 '14 at 21:36

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T() ia a value-initialized prvalue of type T since C++03 when value-initialization was introduced.

It is false for bool, 0 for arithmetic and nullptr for pointer-types.

answered Dec 13 '14 at 21:36

Deduplicator

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score 3 · Answer 2 · answered Dec 13 '14 at 21:37

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Quoting the C++11 FD, [expr.type.conv]/2:

The expression T(), where T is a simple-type-specifier or typename-specifier for a non-array complete object type or the (possibly cv-qualified) void type, creates a prvalue of the specified type, whose value is that produced by value-initializing (8.5) an object of type T; no initialization is done for the void() case.

And value-initialization implies zero-initialization for scalars.

answered Dec 13 '14 at 21:37

Columbo

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That quote again from you ... +1. – Deduplicator Dec 13 '14 at 21:38
How is your average Joe supposed to use a language whose specs look like a draft law on sheep breeding programmes, I wonder... – kuroi neko Dec 13 '14 at 21:48
Just curious but are you really 17? How did you get so good? – David G Dec 14 '14 at 03:34

what is bool(), int(), and double() in c++/c++11?

2 Answers2