java基础语法

package base;

public class Demo01 {

    String name;
    int age;

    final static Double Pi=3.1415962;

    final  Double score=99.0;

    public static void main(String[] args) {
        int i=10;
        System.out.println(i);//10

        Demo01 demo01 = new Demo01();

        System.out.println(demo01.age);//0
        System.out.println(demo01.name);//null

        System.out.println(Pi);//3.1415962

        System.out.println(demo01.score);//99.0

        text();//hihi

        text2();//1111100000000
    }

    private static void text() {
         String name="hihi";
        System.out.println(name);//hihi
    }


    private  static  String text2(){
        int salary = 2000_0000;
        int years = 55555;
        long res=salary*(long)years;
        System.out.println(res);//1111100000000
        return null;
    }


}