When you makes this:
NumWords myWord = nulll;
only declares the object myWord of type NumWords. not yet create a new
instance. When you writes this:
NumWords myWord = new NumWords();
Or
NumWords myWord = null;
//more code
myWord = new myWord();
creates an new instance of NumWords class .
2010/12/8 Gagan Arora <[email protected]>
> Hello Ning,
>
> 1 and 2 is the syntax for Constructor declaration. Whenever you require an
> object of NumWords you will write something like this
>
> NumWords myWord = new NumWords(); *This highlighted code refers the
> constructor and sets the initial values for object myWord according to what
> you will have in 2.*
>
> 3 is syntax for declaration of main method. Just to give you an idea the
> application starts from main method. Consider it as entry point.
>
> Happy Coding
> G
>
> On Wed, Dec 8, 2010 at 6:34 AM, Ning Yun (运宁) <[email protected]>wrote:
>
>> Hello my teacher and classmates,
>>
>> I'm studying InputFromKeyboard lesson from Javapassion. I found when
>> we use swing classes, we sometimes add a statement "Public classname()
>> {}"(as first two example), while we don't do that sometimes(as the
>> last example). What is this statement used for? What's the difference
>> between using it and not using it?
>>
>> --------------------------
>> 1."public class InputFromKeyboardJOptionPane {
>>
>> /** Creates a new instance of InputFromKeyboardJOptionPane */
>> public InputFromKeyboardJOptionPane() {
>> }"
>> --------------------------
>> 2. "import javax.swing.JOptionPane;
>>
>> public class NumWords {
>>
>> /** Creates a new instance of NumWords */
>> public NumWords() {
>> }"
>> ----------------------------
>> 3. "import javax.swing.JOptionPane;
>>
>> public class Grades {
>>
>> public static void main(String[] args) { "
>> --------------------------------
>>
>> Thank you very much in advance.
>>
>> Best regards,
>> Ning
>>
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>
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