[Solved] Array data is ‘lost’ after passing the array to another object

Question

First, your code is not valid C++. Declaring empty arrays using [] does not exist in C++.

So the first thing is to turn this into valid C++ that still preserves what you’re trying to accomplish. One solution is to use std::vector:

#include <vector>
class Universe {
public: 
    std::vector<Star> stars;
    std::vector<Planet> planets;
public: 
    Universe(const std::vector<Star>& st, 
             const std::vector<Planet>& pl) : stars(st), planets(pl) {}
};

Note the replacement of the non-C++ code with std::vector. Also note that we initialize the vectors using the initializer-list.

Last, note that we no longer need to keep the sizes as separate member variables. Why? Because a vector knows its size by calling the vector::size() member function. For example:

  for(int i = 0;i < starsLength;i++) {

can be replaced with

  for(int i = 0;i < stars.size();i++) {

In your buildUniverse function, use the following changes:

Universe buildUniverse(int size, int seed) {
    Point bounds = Point{static_cast <float> (size),static_cast <float> (size)}; //0,0 to size,size
    int starCount = min(size/10,random(size/5));
    int planetCount = min(size/3,random(size));

    std::vector<Star> stars(starCount);
    std::vector<Planet> planets(planetCount);

    //...
    Universe uni(stars, planets);

The rest of the code stays the same. Now, if after the call to create the Universe, you see that the vectors didn’t pass the correct information, then look further. The code above conforms to “normal” C++, such that we can go further and figure out the issue.

Accepted Answer