前面还有一部分代码我省去了
public class Account {
String customerId;
String accountNo;
float balance;
public Account(String customerId,String accountNo,float balance){
this.customerId = customerId;
this.accountNo = accountNo;
if (balance < 0) {
System.out.println("余额不能为负");
} else {
this.balance = balance;}
}
public Account(String customerId,String accountNo){
this.customerId = customerId;
this.accountNo = accountNo;
this.balance = 0;
}
public void deposit(float amount){
this.balance = balance + amount;
return ;
}
public void withdraw(float amount){
if (amount>balance){
System.out.println("账户余额不足！");
}else {
this.balance = balance - amount;}
return ;
}
public float getBalance(){
return balance;
}
}
public class Ex4_3 {
public static void main(String args[]) {
//为张三李四开设账户
Customer zhangsan = new Customer("1","zhangsan",'F');
Customer lisi = new Customer("2","lisi",'M');
Account zhangsan1 = new Account(zhangsan.getID(),"zhangsan1",2000);
Account zhangsan2 = new Account(zhangsan.getID(),"zhangsan2");
Account lisi1 = new Account(lisi.getID(),"lisi",3000);
//张三第一个账户取款500
if (!zhangsan1.withdraw(500))
{System.out.println("zhangsan1余额不足，取款失败！");
}
//张三从第一个账户转账1000到第二个账户中
if (!zhangsan1.withdraw(1000))
{System.out.println("zhangsan1余额不足，转帐失败！");
}
else
zhangsan2.deposit(1000);
//李四取款300
if (!lisi1.withdraw(300))
{System.out.println("lisi余额不足，取款失败！");
}
//查询张三与李斯的客户信息与账户余额
System.out.println(zhangsan);
System.out.println("张三的第一个账户余额为 " + zhangsan1.getBalance());
System.out.println("张三的第二个账户余额为 " + zhangsan2.getBalance());
System.out.println(lisi);
System.out.println("李四的余额为" + lisi1.getBalance());
}
}
【问题】就是在执行文件时 指出if (!lisi1.withdraw(300))这里不能使用空类型，求大神解答一下 不懂啊