Try to work with the helping elements before looking at the solution…

Helping elements

• make a new method in TraModel: private boolean treeSurvival()

• given a tree, the method will return true if it survives, or false if it dies (the tree does not need to be passed to the method)

• possible code for this method:

    double survivalProba = 0.98;
    double proba = random.nextDouble (); // [0,1[
    return proba <= survivalProba; // returns true in 98% of the cases

• in processEvolution (), in the trees growing loop, for each tree, check the result of the treeSurvival () method

• if it returns false, skip the tree growth and addition in newScene: it is dead, it will not be present in the newScene

• the 'continue' statement jumps directly to the next iteration, to be called if the tree is dead, before its addition in newScene

• compile, run a new simulation to check if trees disappear with this mortality feature

A possible solution