計劃得到改變（四捨五入幫助）

我想圓我的計劃鎳的數量（有沒有硬幣了）。所以如果我輸入1.44，它應該是1.40，如果我有1.46，它應該是1.50。請幫忙！計劃得到改變（四捨五入幫助）

import java.util.Scanner; 

public class MakingChange 
{ 

    private static Scanner scanner; 

    public static void main(String[] args) 

    { 
     scanner = new Scanner(System.in); 
     double amount = 0; 
     while (true) { 
      try { 
       amount = Double.parseDouble(scanner.nextLine()); 
       break; // will only get to here if input was a double 
      } catch (NumberFormatException ignore) { 
       System.out.println("INVALID\r\n$"); 
      } 
     } 

     //calculating amount of change in cents 
     int remainingAmount = (int)(amount * 100.00); 
     //toonies 
     int numberofToonies = (int) (remainingAmount/200.00); 
     remainingAmount = remainingAmount % 200; 
     //loonies 
     int numberofLoonies = (int) (remainingAmount/100.00); 
     remainingAmount = remainingAmount % 100; 
     //quarters 
     int numberofQuarters = (int)(remainingAmount/25.00); 
     remainingAmount = remainingAmount % 25; 
     //dimes  
     int numberofDimes = (int)(remainingAmount/10.00); 
     remainingAmount = remainingAmount % 10; 
     //nickels 
     int numberofNickels = (int)(remainingAmount/5.00); 
     remainingAmount = remainingAmount % 5; 
     //rounded value 
     numberofNickels=(int) (((amount -(numberofToonies * 2) - (numberofLoonies *1) - (numberofQuarters *0.25) - (numberofDimes * 0.10) - (numberofNickels * 0.05))+0.04)/0.05); 

System.out.println(".*toonies:" + numberofToonies + ";" + " loonies:" + numberofLoonies + ";" + " quarters:" + numberofQuarters + ";" + " dimes:" + numberofDimes + ";" + " nickels:" + numberofNickels +"$"); 


     } 

}

來源

2016-04-29 Jane Doe2

那麼究竟如何不工作的代碼？ –

*你可以做到這一點美國式的，如果你有1.44，那麼你得到1和技巧罐子得到0.44：P *也許您正在尋找['Math.round']（https://docs.oracle.com /javase/8/docs/api/java/lang/Math.html#round-double-）。還要注意的是，你不應該使用雙貨幣東西（用'BigDecimal'例如） – 2016-04-29 15:58:04

好，而沒有給我兩個五分，它只會給我一個...四捨五入關閉。此外，當我做得到兩個五分，我想讓它顯示1毛錢而不是兩個鎳 –

我建議十乘以數量，一輪它Math.round()，然後十分回來。

1.46 * 10 = 14.6 
Math.round(14.6) = 15 
15/10 = 1.5 

1.44 * 10 = 14.4 
Math.round(14.4) = 14 
14/10 = 1.4

這可以通過以下拉姆達實現：

d -> Math.round(d * 10)/10.0

指定10.0代替10很重要，因爲Math.round()返回long值，你不想整數divison但浮動師。

你可以看到它在行動上this ideone snippet。

來源

2016-04-29 16:03:25 Aaron

寫這個邏輯到一個可重用的helper方法將是一個不錯的主意，例如'double roundToNickel（double amount）'。 – Andreas

@Aaron，你可以給我的代碼片段？我不確定它會是什麼樣子。另外，爲什麼我不把它乘以0.05，然後除以0.05 –

不要忘記詢問用戶他的投入

public class MakingChange 
{ 
    private static Scanner scanner; 

    public static void main(String[] args) { 

     scanner = new Scanner(System.in); 
     System.out.println("Insert amount:"); 
     double amount = 0; 
     while (true) { 
      try { 
       amount = Double.parseDouble(scanner.nextLine()); 
       break; // will only get to here if input was a double 
      } catch (NumberFormatException ignore) { 
       System.out.println("INVALID\r\n$"); 
      } 
     } 

     // calculating amount of change in cents 
     int remainingAmount = (int) (amount * 100.00); 
     // toonies 
     int numberofToonies = (int) (remainingAmount/200.00); 
     remainingAmount = remainingAmount % 200; 
     // loonies 
     int numberofLoonies = (int) (remainingAmount/100.00); 
     remainingAmount = remainingAmount % 100; 
     // quarters 
     int numberofQuarters = (int) (remainingAmount/25.00); 
     remainingAmount = remainingAmount % 25; 
     // dimes 
     int numberofDimes = (int) (remainingAmount/10.00); 
     remainingAmount = remainingAmount % 10; 

     // nickels 
     int numberofNickels = 0; 
     // if the remaining amount is exactly 5 cents 
     if (remainingAmount == 5) { 
      numberofNickels = 1; 
     } else if (remainingAmount > 5)// round to higher value if remaining 
             // value is greater than 5 cents e.g 
             // 20.68 
     { 
      numberofDimes += 1; 
     } 

     System.out.println(".*toonies:" + numberofToonies + ";" + " loonies:" + numberofLoonies + ";" + " quarters:" 
       + numberofQuarters + ";" + " dimes:" + numberofDimes + ";" + " nickels:" + numberofNickels + "$"); 

    } 
}

來源

2016-04-29 16:30:59 Svetlana

計劃得到改變（四捨五入幫助）

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