创建出dragon和troll的对象 包含攻击造成的伤害及移动的放向距离-Create a class called Monster .A Dragon is a type of Monster that attacks by either breathing fire or clawing (this is a generic attack). It attacks by breathing fire 30　of the time and generically the rest of the time2. When it attacks by breathing fire, it causes between 1 and 50 points of damage　in this case, it also prints a statement to the console, like the generic attack, that includes the name, the class type, the attack type and the damage done.A Troll is also a kind of Monster, but trolls cannot be named Saul or Salomon. If the user of your program attempts to misname a troll, your program should print an error message and name the troll Detritus.