content: /**
   * @author 1diot9
   * @since 2025.5.5
   */
  public class Main {
  
  
      public static void main(String[] args){
          System.out.println("Hello world!");
          final int z = 777;  //常量，不可修改，只能第一次赋值
          byte a = 127;
          short b = 11;
          int c;
          long d = 1233333333333333L;  //最后要加L，不然默认是int
          c = b;
          c = 1_000_000; //_无影响
          System.out.println(0xA);
          System.out.println(013);    //8进制
  
          c = 2147483647;
          c = c + 1;
          System.out.println(c);  //会溢出
  
          float f = 0.1f; //有小数点默认是double
          System.out.println(f);
          double g = 19.3;
  
  
          char str = 65;
          System.out.println(str);
  
          String s = "sss,你好";    //String是对象类型，而不是基本类型
          System.out.println(s);
  
          System.out.println(8/3);    //省略小数
          System.out.println(8.0/3);
  
  
          //===========================运算
  
          int aa = 10;
          int bb = 20;
          bb = (aa = 3) * (-aa + 8);
          System.out.println(bb);     //15
  
          aa = 8;
          bb = -aa++ + ++aa;  //先a++，aa = 8，再-aa，aa = 9，再++aa，aa = 10
          System.out.println(bb);
  
  
      }
  }