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+====== My Solution on CS106A - Section 20 - Problem 3 - Random Circles ======
+This is my Solution on CS106A - Section 20 - Problem 3 - Random Circles from the [[http://see.stanford.edu/see/courseinfo.aspx?coll=824a47e1-135f-4508-a5aa-866adcae1111|Computer Science Course CS106A of Prof. Mehran Sahami]] at the [[http://www.stanford.edu|STANFORD University]].
+**Question:** On some runs of this program you might not see ten circles. Why?
+**My Answer:** Since there is no special controlling on where to place new circles on the canvas it is possible that it puts a new larger circle on top of an older smaller circle, covering the older circle completly. So its possible to have LESS THEN 10 circles visible on the canvas.
+===== My Code: =====
+<code java RandomCircles.java>
+/*
+ * File: RandomCircles.java
+ * -------------------
+ * Name: Axel Werner [mail@awerner.myhome-server.de]
+ * Section Leader:
+ *
+ * CS106A - Section 20 - Problem 3 - Random Circles
+ *
+ * Write a GraphicsProgram that draws a set of ten circles
+ * with different sizes, positions, and colors.
+ * Each circle should have a randomly chosen color,
+ * a randomly chosen radius between 5 and 50 pixels, and a
+ * randomly chosen position on the canvas, subject to the
+ * condition that the entire circle must fit inside the
+ * canvas without extending past the edge.
+ *
+ */
+import acm.graphics.*;
+import acm.program.*;
+import acm.util.*;
+import java.awt.*;
+/**
+ * Program to display random colored and random size circles
+ * on the canvas. Number of circles and valid radiuses are
+ * configurable by static finals (class variables).
+ *
+ * @author Axel Werner [mail@awerner.myhome-server.de]
+ *
+ */
+public class RandomCircles extends GraphicsProgram {
+	private static final int MAX_CIRCLES = 10;
+	private static final int MIN_RADIUS = 5;
+	private static final int MAX_RADIUS  = 50;
+/**
+ * Main Program
+ */
+	public void run(){
+		final int CANVAS_WIDTH = getWidth();
+		final int CANVAS_HEIGHT = getHeight();
+		for(int circ=MAX_CIRCLES; circ > 0 ; circ--){
+			int r = getRand(MIN_RADIUS,MAX_RADIUS);
+			/* Note:
+			 * Formular "CANVAS_WIDTH-2*r" makes sure that the
+			 * Object stays completly within the Canvas surface
+			 * and does not exceed edges.
+			 */
+			int xPos = getRand(0,CANVAS_WIDTH-2*r);
+			int yPos = getRand(0,CANVAS_HEIGHT-2*r);
+			addCircle(r, xPos, yPos);
+		}
+	}
+	/**
+	 * Method to put Circle GObjects of random Color on the Canvas.
+	 *
+	 * @param r a integer Radius value
+	 * @param xPos a integer X position on the Canvas
+	 * @param yPos a integer Y position on the Canvas
+	 */
+	private void addCircle(int r, int xPos, int yPos) {
+		GOval newCircle = new GOval(xPos, yPos, r*2, r*2);
+		newCircle.setFilled(true);
+		Color rndColor = getRandColor();
+		newCircle.setColor( rndColor );
+		newCircle.setFillColor( rndColor );
+		add(newCircle);
+	}
+	/**
+	 * Method to return a random Color
+	 *
+	 * @return a random Color.
+	 */
+	private Color getRandColor() {
+		RandomGenerator rnd = RandomGenerator.getInstance();
+		return rnd.nextColor();
+	}
+	/**
+	 * Method to return a random Number between
+	 * the given min + max Parameters.
+	 *
+	 * @param min minimal integer value to pick a random number from.
+	 * @param max maximum integer value to pick a random number from.
+	 * @return a random integer number
+	 */
+	private int getRand(int min, int max) {
+		RandomGenerator rnd = RandomGenerator.getInstance();
+		return rnd.nextInt(min, max);
+	}
+}
+</code>
+ --- //[[mail@awerner.myhome-server.de|Axel Werner]] 2012-04-03 22:49//
+{{tag>java karel stanford university cs106 computer science learning programming}}