在转换货币然后将其除以美元金额时，我正在努力寻找剩余货币。此外，创建要转换的最小货币量也是一个问题。我理解我的代码很多，但这是我的第一个Java项目。任何帮助将非常感激。
/* Currency Conversion
*/
import java.util.Scanner;//to get keyboard input from user
public class Currency {
/**
* Converts from a foreign currency to US Dollars. Takes a
* deduction for the transaction fee. Displays how many of
* each bill and coin denomination the user receives.
*
* @param args no parameters expected
*/
public static void main(String[] args)
{
final double SEK_CONVERSION_RATE = .14;
/*
* You'll need a variable or constant for the transaction fee.
* (3% is fairly typical.) You'll also need a variable or
* constant for the minimum transaction fee.
*/
double transactionFee = .03;
final double MIN_TRANSACTION_FEE = 10.00;
/*
* You're going to need a variable for the amount of that
* currency the user wants to convert.
*/
//Before you can ask the user for input, you need a Scanner so you can read
//that input:
Scanner keyboard = new Scanner(System.in);
/*
* Now you're ready to interact with the user. You'll want
* to greet them and let them know what currency they can convert
* and what the rate of exchange is.
*/
System.out.print("Hello there, welcome to your one and only stop for Swedish Krona conversions. The exchange rate currently sits at .14" );
/*
* You should also let them know about the transaction fee.
*/
System.out.println(" The minimum transaction fee is $10.00 USD.");
/*
* Now you're ready to prompt the user for how much money they
* want to convert.
*/
System.out.println("How many Swedish Krona would you like to convert to US Dollar?");
double userCurrencyInput = keyboard.nextDouble();
/*
* And then use the Scanner to read in that input and initialize your
* variable for currency:
*/
double calculatedCurrInput = (userCurrencyInput*SEK_CONVERSION_RATE);
/* setting up casting to use later in program */
int calculatedCurrInputInt = (int) (calculatedCurrInput);
/*
* You've received an amount in a foreign currency, but you're going
* to need the amount in dollars. Furthermore, you're going to need
* to know the number of 20's, 10's,5's, 1's, quarters, dimes, nickels
* and pennies. And you're going to need to know the transaction fee.
* These should all be stored in variables.
*/
double totalTransaction = (userCurrencyInput*transactionFee + calculatedCurrInput);
int totalTransactionInt = (int) (totalTransaction);
/*Need to define the remainder correct to make change*/
System.out.println("The conversion is " + calculatedCurrInput);
int twentyDollar = 20;
int twentyDollarBills = calculatedCurrInputInt/twentyDollar;
int remainderOfTwenty = calculatedCurrInputInt%twentyDollar;
int tenDollar = 10;
int tenDollarBills = remainderOfTwenty/tenDollar;
int remainderOfTen = remainderOfTwenty%tenDollar;
int fiveDollar = 5;
int fiveDollarBills = remainderOfTen/fiveDollar;
int remainderOfFive = remainderOfTen%fiveDollar;
int oneDollar = 1;
int oneDollarBills = remainderOfFive/oneDollar;
int remainderOfOnes = remainderOfFive%oneDollar;
double remainderOfOnesDBL = (double) remainderOfOnes;
double quarter = .25;
double numberOfQuarters = remainderOfOnesDBL/quarter;
double remainderOfQuarters = remainderOfOnesDBL%quarter;
double dimes = .10;
double numberOfDimes = remainderOfQuarters/dimes;
double remainderOfDimes = remainderOfQuarters%dimes;
double nickels = .05;
double numberOfNickels = remainderOfDimes/nickels;
double remainderOfNickels = remainderOfDimes%nickels;
double pennies = .01;
double numberOfPennies = remainderOfNickels/pennies;
/*
* Now you're ready to calculate the amount in USD.
*/
/*
* Determine what the transaction fee would be, based on the
* percentage.
*/
double totalTransactionFee = (userCurrencyInput*transactionFee);
System.out.println("The transcation fee for your currency exchange would be $" + totalTransactionFee + " US.");
/*
* If the transaction fee is less than the minimum transaction
* fee, you'll need to charge the minimum transaction fee.
* (Hint, the Math class has min and max methods that receive
* two numbers and return either the smaller or larger of those
* two numbers.)
*/
/*
* You'll need to deduct the transaction fee from the total.
*/
/*
* Calculate the number of $20's they'll receive
*/
/*
* How much is left?
*/
/*
* Next do the same for $10's, $5's, etc.
*/
/*
* Finally, let the user know how many dollars their foreign currency
* converted to, what was deducted for the transaction fee, and how
* many of each denomination they are receiving.
*/
System.out.println("The amount of 20's is " +twentyDollarBills);
System.out.println("The amount of 10's is " +tenDollarBills);
System.out.println("The amount of 5's is " +fiveDollarBills);
System.out.println("The amount of 1's is " +oneDollarBills);
System.out.println("The amount of quarters is " +numberOfQuarters);
System.out.println("The amount of dimes is " +numberOfDimes);
System.out.println("The amount of nickels is " +numberOfNickels);
System.out.println("The amount of pennies is " +numberOfPennies);
}//end main
}//end Currency
答案 0 :(得分：0)
首先，您不应该从double转换为int s，因为您将丢失小数点后的数量。 e.g。
double num = 1.9;
int number = (int) num;
System.out.println(number);
将打印
1
另外，如果你这样做
System.out.println(num % 1);
你得到了
0.8999999999999999 // not quite 0.9, which is what you were expecting
正如@Laf指出的那样，请改用BigDecimal。
BigDecimal SEK_CONVERSION_RATE = new BigDecimal(".14");
String userInput = keyboard.nextLine();
// Better precision constructing from a String
BigDecimal userCurrencyInput = new BigDecimal(userInput);
BigDecimal calculatedCurrInput = userCurrencyInput.multiply(SEK_CONVERSTION_RATE);
希望你可以从那里解决剩下的问题。
提示：BigDecimal有一个方法divideAndRemainder()，返回BigDecimal[]，其中第一部分是商，第二部分是余数。