输入 3 个正数，判断能否构成一个三角形

import java.util.Scanner;

public class San {
    San()
    {

    }

    public static void main(String[] args) {
        double a;
        double b;
        double c;
        System.out.println("请输入三个数");
        Scanner in = new Scanner(System.in);
        a = in.nextDouble();
        b = in.nextDouble();
        c = in.nextDouble();
        if(a<=0 || b<=0 || c<=0){
            System.out.println("请输入正数：");
        }
        if((a+b)>c&&(a+c)>b&&(b+c)>a){
            System.out.println("是三角形");
        }else{
            System.out.println("不是三角形");
        }
    }
}