struct UIQstate{ unsigned int left,right,up,down,jump,shoot; UIQstate(): left(0), right(0), up(0), down(0), jump(0), shoot(0) {} unsigned int size() const {return 6;}};C++ default initialization
Author
Is there any way to get numerical types default initialized to 0 in C++ without explicitly initializing them? It seems like there should be a better way to code this.
Would this:
UIQstate(): left(), right(), up(), down(), jump(), shoot() {}
Even if jyk's code works (I think it should), I wouldn't use it: The code is less obvious than the OP's.
struct UIQstate{ enum ACTIONS{left,right,up,down,jump,shoot,enum_end}; unsigned int actions[enum_end]; UIQstate(): actions() {} unsigned int size() const {return static_cast<unsigned>(enum_end);}};
Author
One downside of that is that it complicates any code which uses the struct. For example,
Is a little less readable than
++myState.at(UIQstate::DOWN);Is a little less readable than
++myState.down;
A slightly different variation:
Sure it's not as readable as it could be, but it certainly reduces the amount of work it takes when you want to provide UIQstate::operator+(const UIQstate&), UIQstate::operator*, and etc. This is especially useful for a RPG stats structure, for example.
However, if it's readability you're going for, then what you currently have is the best way to go.
class UIQstate {public: enum Actions { left, right, up, down, jump, shoot, num_actions };public: UIQstate() : actions() { // C4351 }public: unsigned& operator[] ( Actions idx ) { return actions[ static_cast<int>( idx ) ]; } const unsigned& operator[] ( Actions idx ) const { return actions[ static_cast<int>( idx ) ]; } unsigned numActions() const { return num_actions; }private: unsigned actions[num_actions];};int main () { UIQstate t; t[UIQstate::up] ++; cout << t[UIQstate::up] << endl;}Sure it's not as readable as it could be, but it certainly reduces the amount of work it takes when you want to provide UIQstate::operator+(const UIQstate&), UIQstate::operator*, and etc. This is especially useful for a RPG stats structure, for example.
However, if it's readability you're going for, then what you currently have is the best way to go.
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