麻烦将对象传递给单独的类中的方法

时间:2015-03-29 23:43:12

标签: java object parameters compareto

所以我第一次编写自己的类,我唯一​​无法弄清楚的方法是compareTo方法,它应该有一个参数:一个SavingsAccount对象。将它命名为你想要的。 “

public int compareTo(SavingsAccount secAccount)
{
    int result;
    if ( balance > secAccount.getBalance() )
        result = 1;
    else if ( balance == secAccount.getBalance() )
        result = 0;
    else
        result = -1;

    return result;
}

当我尝试编译时,我收到此错误:
错误:缺少return语句}

在客户端(由我的教授编写,我不应该编辑)这是调用我的compareTo方法的行:

if ( savings1.compareTo(savings2) > 0 )
        System.out.println("[client] Savings1 has the larger balance");
    else if (savings1.compareTo(savings2) == 0 )
        System.out.println("[client] Savings1 and Savings2 "
        + "have the same balance");
    else
        System.out.println("[client] Savings2 has the larger balance");

根据我的理解, savings2 正在传递给compareTo,然后在我的SavingsAccount类中,参数 secAccount 作为对象SavingsAccount。

2 个答案:

答案 0 :(得分:0)

您可以执行类似的操作,而不是声明int结果。

public int compareTo(SavingsAccount secAccount)
{
    if ( balance > secAccount.getBalance() )
        return 1;
    else if ( balance == secAccount.getBalance() )
        return 0;
    else
        return -1;
}

除非您需要该结果变量,否则这将起作用。当你可以这样做的时候,不需要编写变量的额外代码设置值。

答案 1 :(得分:0)

你可能只是有一个迷路的大括号。这是一个完整的工作示例:

文件Test.java的内容:

package com.jlb;

public class Test{

    public static void main(String[] args)
    {
        SavingsAccount savings1 = new SavingsAccount(200);
        SavingsAccount savings2 = new SavingsAccount(100);

        if ( savings1.compareTo(savings2) > 0 )
            System.out.println("[client] Savings1 has the larger balance");
        else if (savings1.compareTo(savings2) == 0 )
            System.out.println("[client] Savings1 and Savings2 "
            + "have the same balance");
        else
            System.out.println("[client] Savings2 has the larger balance");
    }


}

文件内容SavingsAccount.java:

package com.jlb;

public class SavingsAccount {

    private int balance = 0;

    public SavingsAccount(int amount){
        this.balance = amount;
    }
    public int getBalance(){
        return this.balance;
    }

    public int compareTo(SavingsAccount secAccount)
    {
        int result;
        if ( balance > secAccount.getBalance() )
            result = 1;
        else if ( balance == secAccount.getBalance() )
            result = 0;
        else
            result = -1;

        return result;
    }
}

您可以在创建savings1和savings2时通过更改值来测试它,然后在Eclipse中将其作为Java程序运行,或者在您喜欢的IDE中运行它。