Problem with the for loop count variable - compiler expects a class!

[Mohammed Azeem]

Good Morning,

I've stepped up from tutorials but I'm still a beginner. I am coding my own "experiments" for practice.

At line 10 in the listing below the loop count variable is "i". It is initialised in the loop and has a life only within the loop.

When I build the project, Netbeans thinks the variable i is a class and reports this error at line 10:

illegal start of expression
cannot find symbol
symbol: class i
location: class MyPanel


Can't see what I'm doing wrong. Anybody help?


By the way the structure of the project is:

* Class MyRectangle defines a rectangle object.
It has a constructor that takes an integers width and height as parameters and then calculates the co-ords of the corners with the rectangle centred at (400,400).

* The class MyPanel (the listing which is shown below) is a JPanel object on to which MyRectangle objects are drawn.

* MyPanel is then displayed in the contentpane of a JApplet.

I have succeeded in drawing one rectangle, now I want to extend the experiment by drawing three concentric rectangles - hence the "for" loop which creates three instances of the MyRectangle class.

Thanks.

import javax.swing.JPanel;
import java.awt.Graphics;

public class MyPanel extends JPanel {
    int a;
    int b;
    
    MyRectangle rectangle;
    
        for (int i=1; i<=3; i++) {
            a = i*100;
            b = i*100;
            rectangle = new MyRectangle(a,b);
        
        }
            

   // int[][] turnrect = rectangle.doRotate();  commented out, not needed for project experiment
    
    public void paint(Graphics g) {
        g.drawLine(rectangle.rectarray[0][0], rectangle.rectarray[1][0], rectangle.rectarray[0][1], rectangle.rectarray[1][1]);
        g.drawLine(rectangle.rectarray[0][1], rectangle.rectarray[1][1], rectangle.rectarray[0][2], rectangle.rectarray[1][2]);
        g.drawLine(rectangle.rectarray[0][2], rectangle.rectarray[1][2], rectangle.rectarray[0][3], rectangle.rectarray[1][3]);
        g.drawLine(rectangle.rectarray[0][3], rectangle.rectarray[1][3], rectangle.rectarray[0][0], rectangle.rectarray[1][0]);
   
    }
    
}

[Greg Brannon]

The compiler's doing it's best within its limited vocabulary to tell you that the for loop should be inside a method.

[Kemal Sokolovic]

You can't write statements outside methods. Put the for loop inside constructor or another method and it should work.

[Mohammed Azeem]

Damn.... Of course.

[Henry Wong]

Greg Brannon wrote:The compiler's doing it's best within its limited vocabulary to tell you that the for loop should be inside a method.

Well, if the purpose of that code is to initialize that instance variable then a constructor or even an instance initializer would be more appropriate.

Henry

[Nikhil Sagar]

Kemal Sokolovic wrote:You can't write statements outside methods.

We can write statements outside method, but not all.

[Kemal Sokolovic]

Besides fields declaration or definition (initialization), I can't remember of a statement that can stand outside method or initializer block.

[Jeff Verdegan]

Nikhil Sagar wrote:

Kemal Sokolovic wrote:You can't write statements outside methods.

We can write statements outside method, but not all.

Yes, but not the way you're probably thinking.

All statements must be inside a method, a constructor, or an initializer block. If that's what you meant, you're correct. Statements can never go directly inside a class, where the OP put his for loop.

[Paul Clapham]

There's a distinction between statements and definitions. A definition declares a variable:

File secret;

whereas a statement doesn't declare a variable:

secret = new File("/root/hidden.txt");

Note that it's possible to do both at the same time:

File secret = new File("/root/hidden.txt");

And this is classified as a definition, not a statement. So all statements must be inside a method, a constructor, or an initializer block, but declarations can appear outside of those things.