《解析java程序设计第3章代码》.docVIP

【例3-2】 class AnIntegerNamedX{ int x; public int getX(){ return x; } public void setX(int newX){ x = newX; } } public class Compare_test{ public static void main(String args[]){ AnIntegerNamedX myX = new AnIntegerNamedX(); AnIntegerNamedX anotherX = new AnIntegerNamedX(); myX.setX(1); anotherX.x = 2; System.out.println(myX.x = + myX.getX()); System.out.println(anotherX.x = + anotherX.getX()); } } // 银行帐户 public class Account { // 银行帐户的属性 private double balance = 0; // 存款余额 // 向帐户中存款，存款金额为amount public void deposit(double amount) { balance = balance + amount; } // 从帐户中取款amount元，成功返回true，否则返回false public boolean withdraw(double amount) { if (amount = balance) { balance = balance - amount; return true; } else return false; } // 查询帐户的当前余额 public double getBalance() { return balance; } } // 库存货品 public class Inventory { // 存货的属性 private double quantity = 0; // 存货的数量 private double amount = 0; // 存货的金额 // 验收入库，入库数量和金额分别为qty和amt public void checkIn(double qty, double amt) { quantity += qty; amount += amt; } // 领料出库，出库数量为qty，返回出库成本 public double checkOut(double qty) { // 如果数量余额不足则不作出库 if (quantity qty) return 0; // 计算出库的成本金额， double amt = amount; if (qty quantity) { // 保证存货数量余额为0时存货金额余额也为0 double price = ((long)(amount/quantity*100)) / 100.0; amt = qty * price; } // 减少库存数量与金额 quantity -= qty; amount -= amt; return amt; } // 查询当前的存货数量余额 public double getQuantity() { return quantity; } // 查询当前的存货金额余额 public double getAmount() { return amount; } } // 采用统一透支限额的信用卡帐户 public class CreditCard { // 类属性 private static double maxOverdraft = 1000; // 透支限额 // 实例属性 private double balance = 0; // 存款余额 // 向帐户中存款，存款金额为amount public void deposit(double amount) { balance = balance + amount; } // 从帐户中取款amount元；取款成功返回true，否则返回false public boolean withdraw(double amount) { if (amount = balance + maxOverdraft) { balance = balance - amount; return t