java - 如何将方法中用户输入的所有输出相加？

Question

我正在为 CS 类(class)开发这个程序，希望用户输入每个硬币的金额，向他们显示所述硬币数量的货币值(value)，然后将每个输出的货币相加。

到目前为止，我所拥有的允许某人输入每种硬币的金额并显示多少硬币，但我似乎不知道如何在最后将所有货币值(value)相加。我需要一个单独的方法来调用从每个方法返回的所有资金的金额。任何帮助，将不胜感激!这是我到目前为止所拥有的:

import java.util.*;

public class Coins {
  public static final Scanner CONSOLE = new Scanner(System.in);

  public static void main(String[] args) {
    quarterDollarAmount( );
    dimeDollarAmount( );
    nickelDollarAmount( );
    pennyDollarAmount( );
  }

  public static void quarterDollarAmount( ) {
    System.out.print("Enter the number of quarters: ");
    int quarterAmount = CONSOLE.nextInt( );
    double amount = quarterAmount * 0.25;
    System.out.println(quarterAmount + " quarter are $" + amount);
  }

  public static void dimeDollarAmount( ) {
    System.out.print("Enter the number of dimes: ");
    int dimeAmount = CONSOLE.nextInt( );
    double amount = dimeAmount * 0.1;
    System.out.println(dimeAmount + " dimes are $" + amount);
  }

  public static void nickelDollarAmount( ) {
    System.out.print("Enter the number of nickels: ");
    int nickelAmount = CONSOLE.nextInt( );
    double amount = nickelAmount * 0.05;
    System.out.println(nickelAmount + " nickels are $" + amount);
  }

  public static void pennyDollarAmount( ) {
    System.out.print("Enter the number of pennies: ");
    int pennyAmount = CONSOLE.nextInt( );
    double amount = pennyAmount * 0.01;
    System.out.println(pennyAmount + " pennies are $" + amount);
  }
}

好的，所以我将所有方法更改为与各自的硬币类型类似:

 public static double pennyDollarAmount( ) {
    System.out.print("Enter the number of pennies: ");
    int pennyAmount = CONSOLE.nextInt( );
    double amount = pennyAmount * 0.01;
    System.out.println(pennyAmount + " pennies are $" + amount);
    return amount;
  }

并添加了方法:

public static double totalDollarAmount( ) {
    double quarters = quarterDollarAmount();
    double dimes = dimeDollarAmount();
    double nickels = nickelDollarAmount();
    double pennies = pennyDollarAmount();
    int total = quarters + dimes + nickels + pennies;
    System.out.println("Total amount is $" + total);
  }
}

但是现在，编译器输出显示(由于显而易见的原因，我已经删除了我的系统详细信息):

1 error found:
File: /Users//Documents/Semester 2/CS/Coins.java  [line: 51]
Error: /Users//Documents/Semester 2/CS/Coins.java:51: possible loss of precision
found   : double
required: int

并将光标置于 + in + pennys; 之前。知道这意味着什么吗？

Answer 1

您需要return amount; 并将所有与金钱相关的函数的返回类型从void 更改为double。

public static double quarterDollarAmount( ) {
    System.out.print("Enter the number of quarters: ");
    int quarterAmount = CONSOLE.nextInt( );
    double amount = quarterAmount * 0.25;
    System.out.println(quarterAmount + " quarter are $" + amount);
    return amount;
}

然后在调用函数时捕获变量中的返回值。

double quarters = quarterDollarAmount();
...
double pennies = pennyDollarAmount();

然后您可以将存储在这些变量中的值相加，并对结果执行您想要的操作。

double total = quarters + ... + pennies;