如何让它显示2个小数点？[重复]

Question

我需要这一行是2个小数点。

System.out.println(i + "\t\t" + interest + "\t\t" + principal + "\t\t" + balance);

我的全部代码是

import java.util.Scanner;
public class assignment5dot22 {

    public static void main(String[] args) {

        int numberOfYears;
        double loanAmount;
        double annualInterest;
        double monthlyInterest;
        double monthlyPayment;
        double principal; 
        double balance;
        double interest;

        Scanner input = new Scanner(System.in);

        System.out.print("Loan Amount: ");
        loanAmount = input.nextDouble();
        System.out.print("Number of Years: ");
        numberOfYears = input.nextInt();
        System.out.print("Annual Interest Rate: ");
        annualInterest = input.nextDouble();

        monthlyInterest = annualInterest / 1200;

        monthlyPayment = loanAmount*monthlyInterest / (1 - (Math.pow(1 / (1 + monthlyInterest),
                numberOfYears * 12)));
        balance = loanAmount;

        System.out.println("Monthly Payment: "
                + (monthlyPayment * 100) / 100.0);
        System.out.println("Total Payment: "
                + (monthlyPayment * 12 * numberOfYears * 100) / 100.0);

        System.out.println("\nPayment#\tInterest\tPrincipal\tBalance");

        for (int i = 1; i <= numberOfYears * 12; i++) {
            interest = (monthlyInterest * balance);
            principal = ((monthlyPayment - interest)*100) / 100.0;
            balance = ((balance - principal) * 100) / 100.0;

            System.out.println(i + "\t\t" + interest + "\t\t" + principal + "\t\t" + balance);
        }
    }


}

Answer 1

在这些情况下，您可以使用String.format或直接使用System.out.printf（），如下所示：

System.out.printf("%d \t\t %.2f \t\t %.2f \t\t %.2f\n", i, interest, principal, balance);

对于这些情况，它更具可读性和简洁性。

Answer 2

我建议尝试使用String.format（）作为输出。

e. g.

System.out.println(String.format("%d \t\t %.2f \t\t %.2f \t\t %.2f", i, interest, principal, balance);

字符串格式允许您使用 %d 和 %.2f 显式声明数据的格式（分别为整数和浮点数）