我有一些代码来计算圆的属性:
package circleinfo; import java.util.Scanner; public class Circleinfo { public static void main(String[] args) { Scanner input=new Scanner(System.in); int r; System.out.print("Enter the radius of the circle to find circumference, diameter, and area\n"); r = input.nextInt(); System.out.printf("The circumference is %f\n",(2*r*Math.PI)); System.out.printf("The diameter is %f\n",(r*2)); System.out.printf("The area is %f\n",(r*r*Math.PI)); } }
它计算周长,但不计算其余部分。
Enter the radius of the circle to find circumference, diameter, and area 10 The circumference is 62.831853 Exception in thread "main" java.util.IllegalFormatConversionException: f != java.lang.Integer at java.util.Formatter$FormatSpecifier.failConversion(Formatter.java:4045) at java.util.Formatter$FormatSpecifier.printFloat(Formatter.java:2761) at java.util.Formatter$FormatSpecifier.print(Formatter.java:2708) at java.util.Formatter.format(Formatter.java:2488) at java.io.PrintStream.format(PrintStream.java:970) at java.io.PrintStream.printf(PrintStream.java:871) at circleinfo.Circleinfo.main(Circleinfo.java:30) The diameter is Java Result: 1
r是一个int,r*2也一个int,这意味着不能在第二个打印语句%f中使用。试试%d那里。
r
int
r*2
%f
%d
回想一下,这%f是浮点数,而%d整数。在的文档中对此进行了概述Formatter(请参阅“ 格式化字符串语法”)。
Formatter