十八天学习core java 例子（第一天）

package cj01;

public class Hello{
 public static void main(String[] args){
  System.out.println("Hello world");
 }
}

//###########################

package cj01;

class  Person
{
 int age;
 String name = "hello";
 
 public Person(int a){
  age = a;

 }

 public void setName(String n){
  name = n;
 }
 public int get(){
  return age;
 }

 public void work(){
  System.out.println(name);
 }
} 

//#########################

package cj01;

class Test{
 public static void main(String[] args){
  //
  Person abc = new Person(12);
  //System.out.println(p);
  abc.setName("aaaa");
  
  int i = abc.get();
  System.out.println(i);
 }
}

//#################################

package cj01;

class  Type
{
 public static void main(String[] args)
 {
  boolean flag = true;  //false
  char c = '你';
  char d = '\n';
  System.out.println(d);
  /*
  byte b1 = 34;
  short b0 = 34;
  int b2 = 17834;
  long b3 = 35435435l;
  */
  int ia = 0x55;  //5*16+5*1
  int ib = 023; //3+2*8
  int ic = 34;    //00100010
  System.out.println(ib);

  float f1 = 1.23f;   //f must

  //cast强制类型转换
  int i = 12;
  byte b = (byte)i;

  byte b1 = 12;
  int i1 = b1;

  char c1 = '你';
  int c2 = c1;
  System.out.println(c2);

  int c3 = 97;
  char c4 = (char)c3;
  System.out.println(c4);

  int a=0;
  System.out.println(a);

 }
}