我的一个学校项目有点问题。我们应该写一个Loan类,它将做与贷款相关的事情,比如返回每月付款和贷款的总付款。我的问题是,我有这个代码的具体说明,我绝对不能离开。这是代码:
import java.util.Scanner;
import java.text.DecimalFormat;
import java.lang.Math;
public class Loan
{
public double annualInterestRate = 0;
public int numberOfYears = 0;
public double loanAmount = 0;
public Loan()
{
annualInterestRate = 0.025;
numberOfYears = 1;
loanAmount = 1000;
}
public Loan(double interestRate, int numYears, double amount)
{
setRate(interestRate);
setYears(numYears);
setLoanAmount(amount);
}
public void setRate(double interest)
{
DecimalFormat percent = new DecimalFormat( "0.0%" );
if(interest > 25 || interest < 0)
{
System.out.println("WARNING: Invalid annual interest rate: " + percent.format(interest) + ".");
System.out.println("Current value not changed: " + percent.format(annualInterestRate * 100) + ".");
}
else
{
annualInterestRate = interest;
}
}
public void setYears(int years)
{
if(years > 30 || years <= 0)
{
System.out.println("WARNING: Invalid number of years: " + years + ".");
System.out.println("Current value not changed: " + numberOfYears + ".");
}
else
{
numberOfYears = years;
}
}
public void setLoanAmount(double amnt)
{
DecimalFormat loan = new DecimalFormat( "$#,##0.00" );
if(amnt <= 0)
{
System.out.println("WARNING: Invalid loan amount: " + loan.format(amnt) + ".");
System.out.println("Current value not changed: " + loan.format(amnt) + ".");
}
else
{
loanAmount = amnt;
}
}
public double getAnnualInterestRate()
{
return annualInterestRate;
}
public int getNumberOfYears()
{
return numberOfYears;
}
public double getLoanAmount()
{
return loanAmount;
}
public double getMonthlyPayment()
{
double monthly = annualInterestRate/12;
double monthlyPayment = (loanAmount * monthly)/1 - (1/(1 + monthly));
monthlyPayment = Math.pow(monthlyPayment, 12);
return monthlyPayment;
}
public double getTotalPayment()
{
double totalPayment = getmonthlyPayment() * 12;
return totalPayment;
}
public String toString()
{
DecimalFormat percent = new DecimalFormat( "0.0%" );
DecimalFormat loan = new DecimalFormat( "$#,##0.00" );
String interestRate = percent.format(annualInterestRate);
String numOfYears = Integer.toString(numberOfYears);
String loanAmnt = loan.format(loanAmount);
String total = "Annual Interest Rate:t" + interestRate + "nNumber of Years:tt" + numOfYears + "nLoan Amount:ttt" + loanAmnt;
return total;
}
}
我的问题是getTotalPayment方法。如果我没有将monthlyPayment声明为字段(如annualInterestRate)或将其传递给getTotalPayment方法,它就无法访问monthlyPay变量。问题是,getTotalPayment不允许有参数,我们也不允许有比她指示我们拥有的三个字段更多的字段,这三个字段将在代码开头声明。那么,我的问题是:有没有一种方法可以让变量monthlyPayment可用于getTotalPayment,而不需要让monthlyPay成为字段或给getTotalPayment一个参数?
您的getTotalPayment()
方法中存在拼写错误。
您要做的是在应该调用getMonthlyPayment()
的时候调用方法getmonthlyPayment()
。
如果你错过了我答案中的细微差别,当你想要大写的"m"时,你就用小写的"m"。
我不完全确定这是否是你的问题,但这是我的IDE告诉我的唯一语法错误。
在修改后的代码中,在调用getMonthlyPayment()
时需要使用大写M
。