簡單的貨幣值，不知道如何採取輸入和輸出貨幣

Question

寫一個封裝硬幣的概念的類，假設硬幣具有以下屬性：一些宿舍，一些硬幣，一些鎳，和一個便士數量。包含構造函數，評估者和增變器，以及toString和equals方法。

不知道如何做到這一點的一部分：

• 還編寫了以下方法：一個小數點後二顯著數字，和其他人返回的錢回來的錢在美元符號總量宿舍，硬幣，鎳和便士。編寫一個接受用戶輸入的客戶端類來測試你的類中的所有方法。

  public class CoinsApp { 
  
  public static void main(String[] args) { 
  
  
  
  Coins c = new Coins(); 
  Scanner scan = new Scanner(System.in); 
  System.out.print("Enter the number of Quarters: "); 
  int q = scan.nextInt(); 
  
  System.out.print("Enter the number of Dimes: "); 
  int d = scan.nextInt(); 
  
  System.out.print("Enter the number of nickels: "); 
  int n = scan.nextInt(); 
  
  System.out.print("Enter the number of pennies: "); 
  int p = scan.nextInt(); 
  
  Coins c1 = new Coins(q,d,n,p); 
  
  
  System.out.println(c1); 
  } 
  } 
  

我會有什麼變化，使我目前的班？

ublic類錢幣{

private int quarters; 
private int dimes; 
private int nickles; 
private int pennies; 

public Coins() { 
    quarters = 0; 
    dimes = 0; 
    nickles = 0; 
    pennies = 0; 
} 

public Coins(int quarters, int dimes, int nickles, int pennies) { 
    this.quarters = quarters; 
    this.dimes = dimes; 
    this.nickles = nickles; 
    this.pennies = pennies; 
} 

/** 
* 
* @return the value of nickles 
*/ 
public int getNickles() { 
    return nickles; 
} 

/** 
* 
* @param nickles 
*/ 
public void setNickles(int nickles) { 
    this.nickles = nickles; 
} 

public int getPennies() { 
    return pennies; 
} 

public void setPennies(int pennies) { 
    this.pennies = pennies; 
} 

/** 
* Get the value of dimes 
* 
* @return the value of dimes 
*/ 
public int getDimes() { 
    return dimes; 
} 

/** 
* Set the value of dimes 
* 
* @param dimes new value of dimes 
*/ 
public void setDimes(int dimes) { 
    this.dimes = dimes; 
} 

/** 
* Get the value of quarters 
* 
* @return the value of quarters 
*/ 
public int getQuarters() { 
    return quarters; 
} 

/** 
* Set the value of quarters 
* 
* @param quarters new value of quarters 
*/ 
public void setQuarters(int quarters) { 
    this.quarters = quarters; 
} 

@Override 
public String toString() { 
    return "Coins{" + "quarters=" + quarters + ", dimes=" + dimes + ", nickles=" + nickles + ", pennies=" + pennies + '}'; 
} 

@Override 
public boolean equals(Object obj) { 
    if (obj == null) { 
     return false; 
    } 
    if (getClass() != obj.getClass()) { 
     return false; 
    } 
    final Coins other = (Coins) obj; 
    if (this.quarters != other.quarters) { 
     return false; 
    } 
    if (this.dimes != other.dimes) { 
     return false; 
    } 
    if (this.nickles != other.nickles) { 
     return false; 
    } 
    if (this.pennies != other.pennies) { 
     return false; 
    } 
    return true; 
} 

}

Answer 1

有很多方法來解決這個問題。如果你想看起來很聰明，但是一個簡單的解決方案要好得多，你可以用多態來做到。

基本上你有一個類（除了你主），我會打電話給wallet：

public class Wallet{ 
private int dimes=0; 
//...etc for all denominations 

//We just print the total value, essentially counting coins here 
//Not familiar with american coinage; in this example a dime=5c and a 
//nickel=10c 
public void printDollars(){ 
    float total=0.0; 
    total+=this.dime*5; 
    total+=this.nickel*10; 
    //...etc 
    //Divide by 100 to get value in dollars instead of cents 
    total/=100; 
    //Now to format the output. Java's System.out.format works a lot 
    //like C's printf. 
    System.out.format("%.2f$", total); 
} 

} 

在System.out.format看看更多。

對於返回硬幣，鎳幣等數量的其他部分，你只需要使用getters。