48 lines
1.2 KiB
Java
48 lines
1.2 KiB
Java
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A scoping example
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import java.awt.Container;
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import javax.swing.*;
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public class Scoping extends JApplet
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{
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JTextArea outputArea;
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int x = 1; // instance variable
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public void init()
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{
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outputArea = new JTextArea();
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Container c = getContentPane();
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c.add( outputArea );
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}
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public void start()
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{
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int x = 5; // variable local to method start
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outputArea.append( "local x in start is " + x );
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methodA(); // methodA has automatic local x
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methodB(); // methodB uses instance variable x
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methodA(); // methodA reinitializes automatic local x
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methodB(); // instance variable x retains its value
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outputArea.append( "\n\nlocal x in start is " + x );
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}
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public void methodA()
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{
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int x = 25; // initialized each time a is called
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outputArea.append( "\n\nlocal x in methodA is " + x + " after entering methodA" );
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++x;
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outputArea.append( "\nlocal x in methodA is " + x + " before exiting methodA" );
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}
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public void methodB()
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{
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outputArea.append( "\n\ninstance variable x is " + x + " on entering methodB" );
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x *= 10;
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outputArea.append( "\ninstance variable x is " + x + " on exiting methodB" );
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}
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}
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