求写几个JAVA小程序！急！（1）求圆面积和圆周长，圆的半径用showInputDialog方法输入，所求面积和周长用s

(1). import javax.swing.JFrame;
import javax.swing.JOptionPane;
public class HelloWorld {

public static void main(String args[]){
JFrame ff=new JFrame();
String R=JOptionPane.showInputDialog("请输入圆的半径:");
double r=Double.parseDouble(R);
JOptionPane.showMessageDialog(ff, "圆的面积为："+3.14*r*r+"n"+"圆的周长为："+2*3.14*r);

}
}
(2). import java.util.Scanner;
public class HelloWorld {

public static void main(String args[]){
Scanner scan=new Scanner(System.in);
int a=scan.nextInt();
int b=scan.nextInt();
int c=scan.nextInt();
if(a+b>c&&b+c>a&&a+c>b){

if((a*a==b*b+c*c)||(c*c==a*a+b*b)||(b*b==a*a+c*c))
System.out.print("是直角三角形");

}else
System.out.print("不能构成三角形");
}
}
(3). public static void main(String args[]){
int a=1000,i=0,sum=0;
while(i0){
a=a/10;
i++;

}
System.out.println(i);
}
(5). import java.util.Scanner;
public class HelloWorld {

public static void main(String args[]){
Scanner scan=new Scanner(System.in);

int road=scan.nextInt();
int weight=scan.nextInt();
double sum=0;
if (road