import java.util.Scanner;
public class Ex {
public static void main(String[] args) {
Scanner Lf=new Scanner(System.in);
double a,b,c,d;
System.out.println("请键入a的值:");
a = Double.valueOf(Lf.nextLine());
System.out.println("请键入b的值:");
b = Double.valueOf(Lf.nextLine());
System.out.println("请键入c的值:");
c = Double.valueOf(Lf.nextLine());
System.out.println("请键入d的值:");
d = Double.valueOf(Lf.nextLine());
System.out.println("两点间距离是:"+ Math.pow((Math.pow((x2 - x1),2)+Math.pow((y2 - y1),2)),0.5));
}
}