Appens to array object

I was playing around with d and i stuck in CaStore class, it accepts the user1 but not the user2 data, i get core.exception.RangeError@main.d(60): Range violation, for example to add db.ccuser[0] = user1; without the [0] and next the db.ccuser[0] = user2; without the [0]

import std.stdio;


class CAdata{ string username;}



class Users{

  int age;
  CAdata[] info;



    this(){

      setNull();
    }


    void setNull(){
      age = 0;
      info ~= new CAdata();
    }
}

class CaStore{

    Users[] ccuser;

    this(){
        ccuser ~=  new Users();
    }       
}





void main()
{

    Users user1 = new Users();
    user1.age = 24;
    user1.info[0].username = "bob";

    Users user2 = new Users();
    user2.age = 24;
    user2.info[0].username = "alice";

    CaStore db = new CaStore();
    db.ccuser[0] = user1;
    db.ccuser[1] = user2;
}

You are writing to a position in the array that is out of bounds.

When you declare your array

Users[] ccuser;

its length is initially 0, there is no room for any elements. Then you append one element, yielding a length of 1:

ccuser ~=  new Users();

This is why the first line

db.ccuser[0] = user1;

works but the second one gives you an error:

db.ccuser[1] = user2;

You are writing to index 1, but that is past the end of the array.

You can either:

1. Append to the array instead:

   db.ccuser ~= user2;
   

2. Or increase the length of the array to make room:

   db.ccuser.length = 2;
   db.ccuser[1] = user2; // now there is room for two elements, no error