package com.p14;

public class BusCard {
	private float balance;
	public BusCard() {
		balance=0;
	}
	public float queryBalance() {
		return balance;
	}
	public void charge(float money) {
		balance=balance+money;
	}
	public void swipe(float money) throws CardException{
		if(balance<money) {
			CardException ex=new CardException("余额不足，无法刷卡，请尽快充值!");
			throw ex;
		}else {
			balance=balance-money;
		}
	}

}