例1.2 商品售卖机
package ch2; public class VendingMachine { int price =80; int balance; int total; void showPrompt() { System.out.println("Welcome."); } void insertMoney(int amount) { balance =balance +amount; } void showBalance() { System.out.println(balance); } void getFood() { if(balance >=price) { System.out.println("Here you are."); balance = balance - price; total = total +price; } } public static void main(String[] args) { VendingMachine vm = new VendingMachine(); vm.showPrompt(); vm.insertMoney(100); vm.showBalance(); vm.getFood(); vm.showBalance(); } }
类是定义了这个类的所有对象长什么样,而对象是这个类的一个个具体实例
成员变量与本地变量