如何解决特定于以下问题的类创建问题
我在Java编码问题中遇到了问题，我可以使用一点帮助来理解问题中提到的条件的思考过程（如下所述）。
这个问题的目的是设计一个收银机程序。您的寄存器中当前包含以下纸币/硬币：
一便士：.01 两便士：.02 五便士：.05 十便士：.10 二十便士：.20 五十便士：.50 一磅：1 两磅：2 五磅：5 十磅：10 二十磅：20 五十磅：50
该程序的目的是计算必须退回给客户的硬币/纸币数量最少的找零。请注意，期望有一个面向对象的解决方案-考虑创建类以提高可重用性。
现在在此平台上对此问题有一个类似的帖子，但是我想知道如何在此问题中使用类而不是对面额进行硬编码？如果有人能对此有所启发，我将不胜感激！我已经为此编写了以下代码，根据上述条件更改此代码的任何帮助将不胜感激：
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.io.*;
public class Main {
/**
* Iterate through each line of input.
*/
public static void main(String[] args) throws IOException {
InputStreamReader reader = new InputStreamReader(System.in);
BufferedReader in = new BufferedReader(reader);
try {
double purchasePrice = Double.parseDouble(in.readLine());
double cash = Double.parseDouble(in.readLine());
Main.calculateChange(purchasePrice,cash);
} catch (Exception e) {
System.out.println(e);
}
}
public static void calculateChange(double purchasePrice,double cash) {
float cashBack = (float) (cash - purchasePrice);
if (cashBack < 0) {
System.out.println("ERROR");
return ;
}
else if (cashBack == 0){
System.out.println(0);
}
StringBuilder change = new StringBuilder();
while (cashBack > 0.01) {
if (cashBack >= 50.0) {
change.append("Fifty Pounds");
cashBack -= 50.0;
} else if (cashBack >= 20.0) {
change.append("Twenty Pounds");
cashBack -= 20.0;
} else if (cashBack >= 10.0) {
change.append("Ten Pounds");
cashBack -= 10.0;
} else if (cashBack >= 5.0) {
change.append("Five Pounds");
cashBack -= 5.0;
} else if (cashBack >= 2.0) {
change.append("Two Pounds");
cashBack -= 2.0;
} else if (cashBack >= 1.0) {
change.append("One Pound");
cashBack -= 1.0;
} else if (cashBack >= 0.5) {
change.append("Fifty Pence");
cashBack -= 0.5;
} else if (cashBack >= 0.20) {
change.append("Twenty Pence");
cashBack -= 0.20;
} else if (cashBack >= 0.1) {
change.append("Ten Pence");
cashBack -= 0.1;
} else if (cashBack >= 0.05) {
change.append("Five Pence");
cashBack -= 0.05;
} else if (cashBack >= 0.02) {
change.append("Two Pence");
cashBack -= 0.02;
} else {
change.append("One Pence");
cashBack -= 0.01;
}
change.append(",");
}
change.setLength(change.length() - 2);
System.out.println(change.toString());
// Access your code here. Feel free to create other classes as required
}
}
解决方法
完整的解决方案在这里：
硬币类：保存硬币值及其名称。
public class Coin {
double value;
String name;
public Coin(double value,String name) {
this.value = value;
this.name = name;
}
public double getValue() {
return value;
}
public String getName() {
return name;
}
}
收银机类：它按降序保存不同类型的硬币。
public class CashRegister {
LinkedHashSet<Coin> coins = new LinkedHashSet<>();
public String calculateChange(double purchasePrice,double cash) {
double cashBack = cash - purchasePrice;
if (cashBack < 0) {
System.out.println("ERROR");
return "";
}
StringBuilder change = new StringBuilder();
while (cashBack > 0) {
Iterator<Coin> iterator = coins.iterator();
while (iterator.hasNext()) {
Coin coin = iterator.next();
int count = 0;
while (cashBack >= coin.getValue()) {
count++;
cashBack -= coin.getValue();
}
if (count > 0) {
change.append(count).append(" " + coin.getName());
change.append("\n");
}
}
}
return change.toString();
}
public LinkedHashSet<Coin> init() {
coins.add(new Coin(50,"Fifty Pound"));
coins.add(new Coin(20,"Twenty Pound"));
coins.add(new Coin(10,"Ten Pound"));
coins.add(new Coin(5,"Five Pound"));
coins.add(new Coin(2,"Two Pound"));
coins.add(new Coin(1,"One Pound"));
coins.add(new Coin(0.5,"Fifty Pence"));
coins.add(new Coin(0.2,"Twenty Pence"));
coins.add(new Coin(0.1,"Ten Pence"));
coins.add(new Coin(0.05,"Five Pence"));
coins.add(new Coin(0.02,"Two Pence"));
coins.add(new Coin(0.01,"One Pence"));
return coins;
}
}
实例化和调用收银机以获取找零：
public static void main(String[] args) throws IOException {
InputStreamReader reader = new InputStreamReader(System.in);
BufferedReader in = new BufferedReader(reader);
try {
// Initialise cash register.
CashRegister cashRegister = new CashRegister();
cashRegister.init();
double purchasePrice = Double.parseDouble(in.readLine());
double cash = Double.parseDouble(in.readLine());
// Calculate change.
String result = cashRegister.calculateChange(purchasePrice,cash);
System.out.println(result);
} catch (Exception e) {
System.out.println(e);
}
}
可以通过 init（）方法将任何面额的硬币添加到收银机中。您还可以在收银机中添加很多其他功能，例如
- 保持平衡。
- 支持动态添加新面额。
- 支持动态删除面额。