我如何使用System.out.printf？

我的老师希望我们以格式方法（最底层）显示我们的值，但问题是我们有一个子，她没有告诉我们如何使用它，我的老师不太有帮助。 任何建议或帮助将不胜感激。

public class SphereCalculations { public static void main(String[] args) { //define variables double circumference = 0; double area = 0; double volume = 0; double surfacearea = 0; double radius = 0; Scanner scan = new Scanner (System.in); DecimalFormat dFmt = new DecimalFormat("0.0000"); //prompt for radius System.out.println("Enter the sphere's radius: "); radius = scan.nextDouble(); //calculate values circumference = 2 * Math.PI * radius; area = Math.PI * (Math.pow(radius, 2)); volume = ((4 / 3) * Math.PI) * Math.pow(radius, 3); surfacearea = (4 * Math.PI) * Math.pow(radius, 2); //Display values with println and DecimalFormat System.out.println("Using Println"); System.out.println("The radius: " + radius); System.out.println("Circumference: " + dFmt.format(circumference)); System.out.println("Area: " + dFmt.format(area)); System.out.println("Volume: " + dFmt.format(volume)); System.out.println("Surface Area: " + dFmt.format(surfacearea)); //Display values with format method System.out.printf(); 

Answer 1

这里举几个例子：

（输出显示在嵌入式注释中的双引号内）

注意：System.out.format（）= System.out.printf（）

 import java.util.Calendar; import java.util.Locale; public class TestFormat { public static void main(String[] args) { long n = 461012; System.out.format("%d%n", n); // --> "461012" System.out.format("%08d%n", n); // --> "00461012" System.out.format("%+8d%n", n); // --> " +461012" System.out.format("%,8d%n", n); // --> " 461,012" System.out.format("%+,8d%n%n", n); // --> "+461,012" double pi = Math.PI; System.out.format("%f%n", pi); // --> "3.141593" System.out.format("%.3f%n", pi); // --> "3.142" System.out.format("%10.3f%n", pi); // --> " 3.142" System.out.format("%-10.3f%n", pi); // --> "3.142" System.out.format(Locale.FRANCE, "%-10.4f%n%n", pi); // --> "3,1416" Calendar c = Calendar.getInstance(); System.out.format("%tB %te, %tY%n", c, c, c); // --> "May 29, 2006" System.out.format("%tl:%tM %tp%n", c, c, c); // --> "2:34 am" System.out.format("%tD%n", c); // --> "05/29/06" } } 

（ 来源 ）