Initializing members of data structure members
I just ran into an awkward problem that has an easy fix, but not something I like to do. In my class constructor, I initialize the data members of the data member. Here's some code:
class Button {
private:
// The attributes of the button
SDL_Rect box;
// The part of the button sprite sheet that will be shown
SDL_Rect* clip;
public:
// Initialize the variables
explicit Button(const int x, const int y, const int w, const int h)
: box.x(x), box.y(y), box.w(w), box.h(h), clip(&clips[CLIP_MOUSEOUT]) {}
However, I am getting a compiler error:
C:\Users\Alex\C++\LearnSDL\mouseEvents.cpp|56|error: expected `(' before '.' token|
and
C:\Users\Alex\C++\LearnSDL\mouseEvents.cpp|56|error: expected `{' before '.' token|
Is there a problem initializing an element this way and I need to switch to assignment in the constructor body?
You can only call your member variable constructor in initialization list
. So, if it SDL_Rect
doesn't have constructor
which accepts x, y, w, h
, you must do it in the body of the constructor.
In case St is not under your control and therefore you cannot write the correct constructor.
struct St
{
int x;
int y;
};
const St init = {1, 2};
class C
{
public:
C() : s(init) {}
St s;
};