第五題

import java.io.*;
import java.awt.geom.Point2D;
public class KeyIn {public static void main(String[] args) throws IOException { BufferedReader keyin;
keyin = new BufferedReader(new InputStreamReader(System.in));
double p11, p12, p21, p22, p31, p32;
System.out.println("keyin p11： ");
String n1 = keyin.readLine();
p11 = Double.parseDouble(n1);
System.out.println("keyin p12： ");
String e1 = keyin.readLine();
p12 = Double.parseDouble(e1);
System.out.println("keyin p21： ");
String n2 = keyin.readLine();
p21 = Double.parseDouble(n2);
System.out.println("keyin p22： ");
String e2 = keyin.readLine();
p22 = Double.parseDouble(e2);
System.out.println("keyin p31： ");
String n3 = keyin.readLine();
p31 = Double.parseDouble(n3);
System.out.println("keyin p32： ");
String e3 = keyin.readLine();
p32 = Double.parseDouble(e3);
Point2D.Double p1 = new Point2D.Double(p11, p12);
Point2D.Double p2 = new Point2D.Double(p21, p22);
Point2D.Double p3 = new Point2D.Double(p31, p32);
System.out.println("P1到P2的距離: " + p1.distance(p2));
System.out.println("P2到P3的距離: " + p2.distance(p3));
}
}