Constructors C++, What does the colon after a constructor mean?

Question

Skimming through some code I noticed something I honestly can't wrap my head around in a constructor.
class Terrain { public: Terrain(int movementCost, bool isWater, Texture texture) : movementCost_(movementCost), isWater_(isWater), texture_(texture) {} ... //More code
What sort of wizardry is this? Are those foo_(foo) representing foo = foo_?

See also: http://www.parashift.com/c%2B%2B-faq-lite/init-lists.html — Ferdinand Beyer, May 08 '14 at 17:17
Please read a basic tutorial or at least the C++ faq lite or some such. — Deduplicator, May 08 '14 at 17:31

score 2 · Accepted Answer · answered May 08 '14 at 17:15

2

This is a c++ initialiser list. You have it almost right, foo_(foo) is equivalent to foo_ = foo;

This is useful for when you have a member variable that does not have a default constructor. Without this feature, you would have to make it a pointer.

The initialisations are also executed in the order that the members were declared in the class defenition, not the order they appear in (which should be the same as a matter of style, but isn't necessarily)

answered May 08 '14 at 17:15

wheybags

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This is also required when you have const member variables and when calling base class constructors. – Chris Drew May 08 '14 at 17:24
This is exactly the answer I was looking for. – Francisco Garcia May 08 '14 at 17:30

Constructors C++, What does the colon after a constructor mean?

1 Answers1