C++ classes, help needed

Question

I am new to C++ and trying to understand a code related to OpenCV. It has a class as follow:

class Settings
{
public:
    Settings() : goodInput(false) {}
    enum Pattern { NOT_EXISTING, CHESSBOARD, CIRCLES_GRID, ASYMMETRIC_CIRCLES_GRID };
    enum InputType { INVALID, CAMERA, VIDEO_FILE, IMAGE_LIST };
.
.
.
.
}

what does Settings() : goodInput(false) {} means here. I don't think it is a constructor. Explain this please.

it is an empty inline constructor {} with an initializer list (but only one element) — Micka, Oct 02 '15 at 09:50

score 2 · Accepted Answer · answered Oct 02 '15 at 09:31

2

It is indeed a constructor. What you see after : is called initializer-list and it initializes values before entering the curly brackets.

You should also know that member variables of a class are always initialized before entering the constructor body. If you don't mention a member variable in the initializer list, it will be default initialized.

answered Oct 02 '15 at 09:31

Paolo M

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how to initialize more than one variables in this way? – Ameer Hamza Oct 02 '15 at 11:26
@AmeerHamza `Settings() : goodInput(false), otherVariable(true) {}` – Paolo M Oct 02 '15 at 12:22

score 0 · Answer 2 · answered Oct 02 '15 at 09:32

0

It assigns the (default) initial value false to the member (probably) checking the validity of the input.

answered Oct 02 '15 at 09:32

Ziezi

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C++ classes, help needed

2 Answers2