1.
import java.util.Scanner;

public class test {
public static void main(String[] args) {
Scanner Hy=new Scanner(System.in);
double x1,x2,y1,y2;
System.out.println("请键入X1的值:");
x1 = Double.valueOf(Hy.nextLine());
System.out.println("请键入X2的值:");
x2 = Double.valueOf(Hy.nextLine());
System.out.println("请键入Y1的值:");
y1 = Double.valueOf(Hy.nextLine());
System.out.println("请键入Y2的值:");
y2 = Double.valueOf(Hy.nextLine());
System.out.println("两个点之间的距离是:"+ Math.pow((Math.pow((x2 - x1),2)+Math.pow((y2 - y1),2)),0.5));

}
}
2.求一个整数个位数的和
import java.util.Scanner;

public class test {
public static void main(String[] args) {
Scanner Hy=new Scanner(System.in);
String Hyper;
System.out.println("请输入一个0-1000的整数来求整数各位数的和");
Hyper = Hy.nextLine();
int test = Integer.valueOf(Hyper);
if(test > 0 && test <= 1000) {
int a = test % 2;
int b = test / 10;
int c = test / 100;
System.out.println("总和为:" + (a + b + c));
}
else {
System.out.println("完成!");
}