你的这个是一个很奇怪的程序
1,Test13 is a class, 我建议你用大写来命名
2. i 和 s 是Test13下的private variable(int)/object(String),所以，应该是private int i; private String s;
如果你一定要让它们成为public，那么就必须把它们定义为static: public static int i; public static String s; (although this is very very unusual!! I suggest avoid it)
3.new test13();<<这一行我想你是要建立一个instance of the Test13class, 要建立一个instance/obect, 格式是这样的：
ClassName instaceName = new ConstructorName(parameters);
in this case:
Test13 test = new Test13(); //where the name of test can be varied as u want
4.假设你的i 和s都是public,那么根本没有必要来建立一个新的instance test,要print只要System.out.println(i)就可以.可是我觉得你这里的意图是要用建立的Test13的object来call出i 和s,那么，应该是
System.out.println("i="+test.i);
System.out.println("s="+test.s);
summary as the following:
public class Test13{
private int i;
private String s="";
public Test13(){
i=5;
s="liyang";
}
public static void main(String[] args){
Test13 test = new Test13();
System.out.println("i="+test.i);
System.out.println("s="+test.s);
}
}
//although this progarm works pretty well, but the more general way of doing such thing will be
public class Test13{
private int i;
private String s="";
public Test13(){
i=5;
s="liyang";
}
public int getInt(){ // this is an accessor method which return the value of int i
return i;
}
public String getString(){ // this is an accessor method which returns the String s
return s;
}
public static void main(String[] args){
Test13 test = new Test13();
System.out.println("i="+test.getInt());
System.out.println("s="+test.getString());
}
}
