java从入门到精髓 - Number char double float

public class MyNumber {
 static String s1="您好。";
 public static void main(String[] args) {
  // TODO Auto-generated method stub
  String s2 = "Java";
  System.out.println(s1);
  System.out.println(s2);
        //byte  short int long
  byte mybyte = 124;   //-128-127
  short myshort = 32564; //-32768 - 32767
  int myint=45784612;
  long mylong = 46789451;
  long result = mybyte + myshort +myint + mylong;
  System.out.println("结果为：" + result);
  // float double;
  float f1 = 13.23f;
  double d1 = 4562.12d;
  System.out.println("float f1: " + f1);
  System.out.println("double d1: "+  d1);
  //char;
  char word ='d',word2='@';
  int p = 23045,p2=45213;
  System.out.println("d在unicode 表中的顺序位置为：" + (int)word);
  System.out.println("@在unicode 表中的顺序位置为：" + (int)word2);
  System.out.println("unicode中第23045位是："+(char)p);
  System.out.println("unicode中第45213位是："+(char)p2);
  //转义字符：\ddd,\dxxx,\',\\,\t,\r,\n,\b,\f;
  char c1='\\';
  char char1 = '\u2605';
  System.out.println(c1);
  System.out.println(char1);
  //布尔型：
  boolean b ;
  //boolean b1,b2;
   b = true;
  System.out.println(b);
  //声明常量：
  final double PI = 3.14;
  int age = 23;
  final int number;
        number = 1234;
        age =22;
        System.out.println("常量PI的值为："+PI);
        System.out.println("赋值后number为:"+number);
        System.out.println("int 型变量为："+age);
 }
}