How to initialize a union? [duplicate]

Answer 1

I don't have a State class so I replaced it with an int.

this is my code:

union Ptrlist
{
    Ptrlist *next;
    int *n;
};


int main(int argc, char** argv)
{
    Ptrlist *l = new Ptrlist;

    // I'm using a way c++ allocated memory here, you can change it to malloc.
    l->n = new int;
    *(l->n) = 10;

    // Because you used an union, n's and next's addres is same 
    // and this will output 10
    printf("%d", *(l->next));

    getch();
    return 0;
}

So in this way, n's value is initialized to 10