For Tutorial 5

For Tutorials

Printing Numbers

Drawing Squares

Nested Loops

Looping over Structures

Adding points to a Polygon

Regular Polygon

You can find the coordinates of a regular polygon using sin and cosine.

Change n and r so that you get a hexagon that is twice the size.

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static void drawFlag(Graphics2D g) { Polygon reg = new Polygon(); int r = 35; int n = 5; for (int i=0;i<n;i++) { double a = i*2*Math.PI/n; reg.addPoint((int)(r*Math.cos(a)), (int)(r*Math.sin(a))); } g.setColor(Color.black); g.translate(75,75); g.fillPolygon(reg); }

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Octagons

Draw the octogon 5 times to make the figure shown.

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static void drawFlag(Graphics2D g) { Polygon reg = new Polygon(); int r = 20; int n = 8; for (int i=0;i<n;i++) { double a = i*2*Math.PI/n; reg.addPoint((int)(r*Math.cos(a)), (int)(r*Math.sin(a))); } g.setColor(Color.black); g.translate(75,75); g.translate(-r,-r); g.fillPolygon(reg); g.translate(2*r,2*r); g.fillPolygon(reg); }

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Less Regular Polygons

You can make a different kind of polygon by changing the radius at each step...

Make the radius different for different values of i.

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static void drawFlag(Graphics2D g) { Polygon reg = new Polygon(); int r; int n = 16; for (int i=0;i<n;i++) { double a = i*2*Math.PI/n; if (i==0 || i==2 || i==4) r=40; else r=20; reg.addPoint((int)(r*Math.cos(a)), (int)(r*Math.sin(a))); } g.setColor(Color.black); g.translate(75,75); g.fillPolygon(reg); }

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test text