继承与super用法

package hello;

public class Account {
protected int id;
protected double balance;
protected double annualInterestRate;
public Account(int id, double balance, double annualInterestRate) {
super();
this.id = id;
this.balance = balance;
this.annualInterestRate = annualInterestRate;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public double getBalance() {
return balance;
}
public void setBalance(double balance) {
this.balance = balance;
}
public double getAnnualInterestRate() {
return annualInterestRate;
}
public void setAnnualInterestRate(double annualInterestRate) {
this.annualInterestRate = annualInterestRate;
}
public double getMonthlyInterest(){
return annualInterestRate/12;
}
public void withdraw(double amount){
if(balance>=amount){
balance-=amount;
}else{
System.out.println("余额不足");
}
}
public void despoit(double amount){
balance+=amount;
}
}

package hello;

public class TestAccount {
public static void main(String[] args){
Account acct=new Account(1122,20000,0.045);
acct.withdraw(30000);
System.out.println("余额为:"+acct.getBalance());
acct.withdraw(2500);
acct.despoit(3000);
System.out.println("余额为:"+acct.getBalance());
System.out.println("月利率为:"+acct.getMonthlyInterest());
}
}

package hello;

public class CheckAccount extends Account {
private double overdraft;
public CheckAccount(int id, double balance, double annualInterestRate,double overdraft){
super(id,balance,annualInterestRate);
this.overdraft=overdraft;
}
public double getOverdraft() {
return overdraft;
}
public void setOverdraft(double overdraft) {
this.overdraft = overdraft;
}
public void withdraw(double amount){
if(amount<=balance){
balance-=amount;
}else if(overdraft>=(amount-balance)){
overdraft-=(amount-balance);
balance=0;
}else{
System.out.println("超过可透支额度");
}
}
}

package hello;

public class TestCheckAccount {
public static void main(String[] args){
CheckAccount ca=new CheckAccount(1122,20000,0.045,5000);
ca.withdraw(5000);
System.out.println("账户余额为："+ca.getBalance());
System.out.println("可透支额度为："+ca.getOverdraft());
}
}