A difficult question

[tyang]

Can anyone help me with this? THANK YOU VERY MUCH!

If the java file name is ABC.java.
Why are some classes defined before the public class ABC?
e.g.
class sparse_binary_vector
{
Vector id = new Vector();
}

class sparse_vector
{
Vector id = new Vector();
Vector val = new Vector();
}

public class ABC
{
...
}

[JosAH]

You can define more than one class in a single source file but only one of them can be public, the other classes have to have package scope. More than one class per source file suggests a tight coupling of the non-public classes with the single public class. It can be abused though.

kind regards,

Jos

[tyang]

Thanks a lot JosAH!