有关java、printf和decimals的问题

Question

代码：

import java.util.Scanner;

public class sdusti00lab1 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        double AA = 8.25;
        double CA = 6.50;
        double ACP = 9.00;
        double CPC = 6.25;

        int numA, numC;
        double numSP, numLP;
        Scanner keys = new Scanner(System.in);
        System.out.print(" enter number of adults ");
        numA = keys.nextInt();
        System.out.println(" enter number of children ");
        numC = keys.nextInt();
        System.out.println(" enter number of small popcorn");
        numSP = keys.nextDouble();
        System.out.println(" enter number of large popcorn");
        numLP = keys.nextDouble();
        double  AAddPrice = (numA*AA);
        double  CAddPrice = (numC*CA);
        double  ACPT = ((ACP*.094)*AA);
        double CPCT = ((CPC*.094)*CA);
        double SPTax = (ACP*.094);
        double LPTax = (CPC*.094);
        System.out.println("Adult admission "+"\t"+numA + "\t$" + AAddPrice);
        System.out.println("Child admission  "+"\t"+numC + "\t$" + CAddPrice);
        System.out.println("Adult popcorn  "+"\t\t"+ACP + "\t$" + ACPT);
        System.out.println("Child popcorn  "+"\t\t"+CPC + "\t$" + CPCT);
        System.out.println("Tax  "+"\t\t\t$"+ (SPTax + LPTax));
        System.out.println("Total "+"\t\t\t$"+(AAddPrice+CAddPrice+CPCT+ACPT) ); 
    }
}

我需要更改最后6行代码，以生成一个小数，该小数停在倒数第二个小数处，但我就是不知道怎么做。

Answer 1

使用System.out.printf或System.out.format来完成此操作。使用%.2f打印最多两个小数点。

System.out.printf("Adult admission \t%d\t$%.2f%n", numA, AAddPrice);

Answer 2

有多种方法可以转换数字(浮点数、双精度数、..)转换为带格式的字符串。甲骨文有一个很好的overview值得学习。

这里要理解的重要方面是:该过程由您来工作

A)指定描述输出应该是什么样子的格式

B)使用该格式和要格式化的数字调用格式化程序