我該如何比較java中繼承的兩個值？

我想創建一個程序，檢查哪個帳戶成本最低，但我不知道如何在我的程序中實現此目的。我該如何比較java中繼承的兩個值？

我要選擇的每類的輸出分別比較(dayTimeCost)

這就是我認爲這可能是implemted，但我不知道該怎麼

如果（BronceDayTimeCost < SilverDayTimeCost）{是System.out.print（「\ n該青銅帳戶是最便宜的。」）;}

如果（SilverDayTimeCost < BronceDayTimeCost）是System.out.print {（「\ n該銀帳戶是最便宜的。」）;}

青銅類

public class Bronze { 

    // ----------------- Atributes ----------------------- 



    public int dayMinutes;  // daytime telphone minutes used 

    public double dayTimeCost; //Total daytime calls cost 

    // ------------- CONSTRUCTORS (inputs) --------------- 

    public Bronze(int theDayMinutes) { 
    dayMinutes = theDayMinutes; 
    } 
    // ------------------ METHODS ------------------------ 
    // Calculate Total daytime calls cost 
    public double calcDayTimeCost(double costDay) { 

     dayTimeCost = dayMinutes * costDay; 
     System.out.print("\nCost of daytime calls = " + costDay + "/min"+ 
     "\n\nTotal daytime calls cost = " + dayTimeCost + 
     "\n"); 

     return dayTimeCost; 
    } 

    //toString method to override that in Object 
    public String toString(){ 
    return(
"\n" 
     ); 
    } 

    //Returns the type of account 
    public String type(){ 
    return "Bronze"; 
    } 
}

銀獎

public class Silver extends Bronze { 

    private static final double costDay = 0.22; 

    public Silver(int theDayMinutes) { 
    super(theDayMinutes); 

    } 
    //Returns the type of account 
    public String type(){ 
    return "Silver"; 
    } 

}

主類

import java.util.Scanner; 

public class AccountUser { 

    // ------------------- FIELDS ------------------------  

    // Create instance of Scanner class 
    public static Scanner input = new Scanner(System.in); 
    // variables 
    public static Bronze bron; 
    public static Silver silv; 

    public static int dayMinutes; 

    // ------------------ METHODS ------------------------ 

    public static void main(String [] args) { 

     // Input dayMinutes (with error message) 
     do{ 
     System.out.print("Please daytime telphone minutes used --> "); 
     dayMinutes = input.nextInt(); 
     if (dayMinutes <= 0){System.out.print("\n" + "Input value outside the range!!!" + "\n");} 
     }while(dayMinutes <= 0); 


     // Create new Bronze instance 
     bron = new Bronze(dayMinutes); 
     silv = new Silver(dayMinutes); 
     // Calculate scheme1, scheme2 
     bron.calcDayTimeCost(0.12); 
     silv.calcDayTimeCost(0.22); 


    System.out.println(bron); 
    System.out.println(silv); 
    } 
}

來源

2016-12-05 dr. loop

歡迎堆棧溢出！看起來你正在尋求作業幫助。雖然我們本身沒有任何問題，但請觀察這些[應做和不應該]（http://meta.stackoverflow.com/questions/334822/how-do-i-ask-and-answer-homework-questions/338845＃338845），並相應地編輯您的問題。 –

您應該閱讀更多關於繼承的內容。銀牌不應該繼承銅牌。它應該繼承。（爲了示範而不是需要）從更抽象的東西，比如關卡。 – DejaVuSansMono

可以科爾將return類型的calcDayTimeCost方法轉換爲如下所示的double變量，然後使用if和else條件檢查哪個成本更低。

double bronCost = bron.calcDayTimeCost(0.12); 
double silverCost = silv.calcDayTimeCost(0.22); 
if(bronCost == silverCost) { 
    System.out.print("\nThe Silver and Bronze Accounts are same cost "); 
} else if (bronCost < silverCost){ 
    System.out.print("\nThe Bronze Account is cheapest."); 
} else { 
    System.out.print("\nThe Silver Account is cheapest."); 
}

雖然你的代碼的工作，它不是面向對象編程，即內聯，在一般情況下，我們的內聯創建類與真實世界的物體，但Bronze和Silver兩種不同的元素，即，他們沒有直接關係/相互繼承。

換句話說，當你說ClassAextendsClassB，你是說ClassA IS-A ClassB

因此，另一種方法，這是如下：

public abstract class Metal { 

     //add fields applicable for all metals 

     public double calcDayTimeCost() { 
      //add code here 
     } 
    } 

    public class Bronze extends Metal { 

     //Bronze specific details 
    } 

    public class Silver extends Metal { 

     //Silver specific details 
    }

來源

2016-12-05 22:18:00 developer

我該如何比較java中繼承的兩個值？

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