public void combat(Monster monster){
System.out.println("You Have Encountered a " + monster.getName());
int damage = monster.getDamage();
if (!player.isAlive()) {
gameover();
}
if(!monster.isAlive()){
System.out.println("You Defeated A " + monster.getName());
player.levelUp(); // doesn't exist - you could implement it yourself by placing the level up logic there.
}
// and the rest...
}