Question

BankAccount b0, b1, b2, b3;
    b1=new BankAccount();
    b2=new BankAccount();
    b3=new BankAccount();
    for (int i=0; i<3; i++)
    {
        if (i==0)
            b0=b1;
        else if (i==1)
            b0=b2;
        else
            b0=b3;

和（你刚才看到的是演示的一部分，下面是课堂内容的一部分）

public String toString(double deposit, double withdraw, double fee, double total) {
    String str=name+"'s bank account statement:" + "\nInitial balance: " + balance + 
        "\nDeposit amount: " + deposit + "\nWithdraw amount: " + withdraw + "\nNumber of transactions: "
        + transac + "\nTotal bank fees: " + fee + "Final monthly balance: " + total; 
        return str;

和（演示，我没有包含所有代码，只是因为这仍然是一个开放的任务。

System.out.println(b0);

我真的不知道为什么它不打印字符串的东西:( 所有课程（将在以后删除）

public class BankAccount {
private String name;
private double balance;
private int transac;

public BankAccount() {
    balance=0;
}
public void setName(String accountName) {
    name=accountName;
}
public void setBalance(double accountBalance) {
    balance=accountBalance;
}
public void setTransac(int accountTransac) {
    transac=accountTransac;
}
public String getName() {
    return name;
}
public double getBalance() {
    return balance;
}
public int getTransac() {
    return transac;
}
public double getDeposit(double deposit) {
    return balance+deposit;
}
public double getWithdraw(double deposit, double withdraw) {
    return balance+deposit-withdraw;
}
public double getFee(double fee, int accountTransac, double deposit, double withdraw) {
    fee=10;
    if (transac<20)
        fee+=transac*0.5;
    else if (20<=transac && accountTransac<40)
        fee+=transac*0.25;
    else if (40<=transac && transac<60)
        fee+=transac*0.2;
    else
        fee+=transac*0.1;
    if (balance+deposit-withdraw<400)
        fee+=15;
    return fee;
}
public double finalBalance(double fee, int accountTransac, double deposit, double withdraw) {
    double total=balance+deposit-withdraw-fee;
    return total;
}
public String toString(double deposit, double withdraw, double fee, double total) {
    toString(this.deposit, this.withdraw, this.fee, this.total);
    String str=name+"'s bank account statement:" + "\nInitial balance: " + balance + 
        "\nDeposit amount: " + deposit + "\nWithdraw amount: " + withdraw + "\nNumber of transactions: "
        + transac + "\nTotal bank fees: " + fee + "Final monthly balance: " + total; 
        return str;

}

}

Answer 1

你应该覆盖public String toString()方法（不带参数）：

如果你已经有方法public String toString(double deposit, double withdraw, double fee, double total)，那么使用它：

class BankAccount {

 public String toString() {
  toString(this.deposit, this.withdraw, this.fee, this.total);
}
/* .. */

Answer 2

你已经重载了toString（）方法，为兄弟提供了一组不同的参数。

您想要不带参数覆盖toString（）方法。

例如，如果您的其他toString（）方法的所有参数都是成员字段：

public String toString() {
    String str=name+"'s bank account statement:" + "\nInitial balance: " + balance + 
        "\nDeposit amount: " + deposit + "\nWithdraw amount: " + withdraw + "\nNumber of transactions: "
        + transac + "\nTotal bank fees: " + fee + "Final monthly balance: " + total; 
    return str;
}

Answer 3

其他答案遗漏的重要信息是，当您调用System.out.println(b0)时，java编译器会自动插入对.toString()的调用 - 它是语言定义的一部分{{3} }。

因此，正如其他地方所说，要打印出一个对象，你需要覆盖这个方法。

toString方法不打印我的对象，而是打印内存地址

3 个答案: