圆周长面积.txt

用java实现圆的半径输入

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
/**
 *
 * @author Administrator
 */
public class Test {
    public static void main(String[] args)throws IOException { 
Test t = new Test(); 
 BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); 
String d = br.readLine();
//String d = "6"; 
double girth = t.roundGirth(d); 
System.out.println ("周长是: " + girth); 
double area = t.roundArea(d); 
System.out.println ("面积是: " + area); 
} 

private double roundGirth(String str){ 
double d = 0;//半径 
double roundGirth = 0; 
d = Double.parseDouble(str); 
roundGirth = 2 * d * 3.14; 
return roundGirth; 
} 

private double roundArea(String str){ 
double d = 0;//半径 
double roundArea = 0; 
d = Double.parseDouble(str); 
roundArea = d * d * 3.14; 
return roundArea; 
} 
}