Grove.java

public class Grove {
    public String groveName;
    public Tree trees[];

    public Grove(String groveName){
        this.trees=new Tree[16];
        this.groveName=groveName;
    }

    public int plant(Tree tree){
        for (int i=0; i<trees.length; i++){
            if (trees[i]==null){
                trees[i]= tree;
                return i;
            }
        } 
        return -1;
    }

    public Tree remove(int num){
        Tree oldTree=trees[num];
        trees[num]=null;
        return oldTree;
    }

    public String toString(){
        int count=0;
        for (int i=0;i<trees.length;i++){
            if (trees[i]!=null){
                count+=1;
            }
        }
        return ""+count;
    }
}