class A{
int a;
public:
A(int inA = 0);
int getA;
protected:
void setA(int inA);
};
A::A(int inA)
{
setA(inA)
}
void A::setA(int inA){
//need to set a as static random number
a = inA;
}
int A::getA()const
{
return a;
}
How could I possibly generate a random using a static member for a? I have seen something like this online: Random Number In-Class Initialisation but not really sure how to use it.
The simplest way is probably to make global instances of the PRNG classes.
std::uniform_int_distribution<int> dist;
std::mt19937 rng((std::random_device()()));
struct foo
{
static int bar;
};
int foo::bar = dist(rng);
Of course, put the global objects and initialization in a .cpp file (thanks @AnonMail!).
Using the old (bad) random number facilities, you could use:
int foo::bar = (srand(time(0)), rand());
This is also not great because you've secretly seeded srand which is sort of weird, and rand is bad.
The (arguably) fun way is to do this:
int foo::bar = []() {std::uniform_int_distribution<int> dist; std::mt19937 mt((std::random_device()())); return dist(mt); }();
You use a lambda to create the variables and return the value, eliminating extra objects and putting it all on one line.
I realized I don't think I've seen a lambda used like this before, so I wasn't sure if it would work. My compiler seems fine with it, and it runs as intended, so my assumption would be this is correct.
