简单的货币值，不确定如何输入和输出货币

Question

编写一个封装硬币概念的类，假设硬币具有以下属性：硬币数量、硬币数量、镍币数量和便士数量。包括构造函数、评估器和修改器，以及 toString 和 equals 方法。

不知道如何做这部分：

• 还对以下方法进行编码：一种以美元表示法返回总金额，小数点后两位有效数字，另一种以四分之一、一角、镍和便士的形式返回货币。编写一个接受用户输入的客户端类来测试类中的所有方法。

  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);
  }
  }
  

我必须对我目前的班级做出哪些改变？

公共类硬币{

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

有很多方法可以解决这个问题。如果你想看起来更聪明，你可以用多态来做到这一点，但一个简单的解决方案会更好。

基本上你有一门课（除了你的主课），我称之为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);
}

}

查看System.out.format 了解更多信息。

对于返回硬币、镍币等的数量的另一部分，您只需要使用 getter。