Merge pull request #83 from HarryDulaney/chapter-16-solutions

Chapter 16 solution Ex 11

Author: HarryDulaney

README.md

@@ -166,7 +166,7 @@ Indicates 100% completion of all exercises for that chapter
 		 16</strong></a> - JavaFx UI Controls and Multimedia
 
 <h6>
-Exercises Needed: 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31
+Exercises Needed: 13, 15, 17, 19, 21, 23, 25, 27, 29, 31
 </h6>
 </li><br>
 		<li><a href="https://github.com/HarryDulaney/intro-to-java-programming/tree/master/ch_17"><strong>Chapter 

ch_16/exercise16_11/Exercise16_11.java

@@ -0,0 +1,87 @@
+package ch_16.exercise16_11;
+
+import javafx.scene.Scene;
+import javafx.scene.control.Button;
+import javafx.scene.control.Label;
+import javafx.scene.control.TextField;
+import javafx.scene.layout.VBox;
+import javafx.stage.Stage;
+
+import java.io.File;
+
+/**
+ * **16.11 (Create a histogram for occurrences of letters) Write a program that reads a
+ * file and displays a histogram to show the occurrences of each letter in the file,
+ * as shown in Figure 16.40b. The file name is entered from a text field. Pressing
+ * the Enter key on the text field causes the program to start to read and process
+ * the file and displays the histogram. The histogram is displayed in the center of the
+ * window. Define a class named Histogram that extends Pane. The class contains the property counts that is an array
+ * of 26 elements. counts[0] stores the
+ * number of A, counts[1] the number of B, and so on. The class also contains a
+ * setter method for setting a new counts and displaying the histogram for the new
+ * counts.
+ * <p>
+ * Example Filename input:
+ * C:\Users\Harry\IdeaProjects\intro-to-java-programming\ch_16\exercise16_11\testFile.txt
+ * (Right-click on the testFile.txt and choose 'copy absolute path')
+ */
+public class Exercise16_11 extends javafx.application.Application {
+    private int[] counts = new int[26];
+
+    @Override
+    public void start(Stage primaryStage) throws Exception {
+        Histogram histogram = new Histogram(new int[26]);
+        Label label = new Label("Filename:");
+        TextField fileInputField = new TextField();
+        Button viewHistogramButton = new Button("View");
+        VBox parentBox = new VBox();
+        double WIDTH = 800;
+        histogram.setPrefWidth(WIDTH);
+        double HEIGHT = 500;
+        histogram.setPrefHeight(HEIGHT);
+        parentBox.setPrefWidth(WIDTH);
+        parentBox.setPrefHeight(HEIGHT);
+        VBox.setVgrow(histogram, javafx.scene.layout.Priority.ALWAYS);
+        parentBox.getChildren().add(histogram);
+        parentBox.getChildren().addAll(label, fileInputField, viewHistogramButton);
+        viewHistogramButton.setOnMousePressed(event -> {
+            String filePath = fileInputField.getText();
+            if (filePath.isEmpty()) {
+                return;
+            }
+            File file = new File(filePath);
+            if (!file.exists()) {
+                System.out.println("File does not exist");
+                return;
+            }
+            histogram.setCounts(countLetterFromFile(file, counts));
+        });
+        Scene scene = new Scene(parentBox, WIDTH, HEIGHT);
+        primaryStage.setResizable(false);
+        primaryStage.setScene(scene);
+        primaryStage.show();
+    }
+
+    public static int[] countLetterFromFile(File file, int[] counts) {
+        String s = "";
+        try (java.util.Scanner input = new java.util.Scanner(file)) {
+            while (input.hasNext()) {
+                s = input.nextLine();
+                for (int i = 0; i < s.length(); i++) {
+                    char c = s.charAt(i);
+                    if (Character.isLetter(c)) {
+                        int index = Character.toUpperCase(c) - 'A';
+                        counts[index]++;
+                    }
+                }
+            }
+        } catch (Exception e) {
+            System.out.println("Error reading file");
+            System.out.println("Error Message: " + e.getMessage());
+        }
+
+        return counts;
+    }
+
+
+}

ch_16/exercise16_11/Histogram.java

@@ -0,0 +1,44 @@
+package ch_16.exercise16_11;
+
+import javafx.scene.layout.Pane;
+import javafx.scene.paint.Color;
+import javafx.scene.shape.Rectangle;
+import javafx.scene.text.Text;
+
+public class Histogram extends Pane {
+    private int[] counts;
+
+
+    public Histogram(int[] counts) {
+        this.counts = counts;
+        getChildren().clear();
+        paint();
+    }
+
+    void paint() {
+        getChildren().clear();
+        double frameWidth = getWidth();
+        double frameHeight = getHeight();
+        double unitWidth = frameWidth / counts.length - 10;
+
+        for (int i = 0; i < counts.length; i++) {
+            double labelX = i * unitWidth;
+            double labelY = frameHeight;
+            double unitHeight = counts[i];
+            double unitY = frameHeight - unitHeight;
+            double unitX = i * unitWidth;
+            Text label = new Text(labelX + 5, labelY - 5, (char) (65 + i) + "");
+            Rectangle chartShape = new Rectangle(unitX, unitY - label.getLayoutBounds().getHeight(), unitWidth, unitHeight);
+            chartShape.setFill(Color.WHITE);
+            chartShape.setStroke(Color.BLACK);
+            getChildren().add(chartShape);
+            getChildren().add(label);
+        }
+    }
+
+    public void setCounts(int[] counts) {
+        this.counts = counts;
+        // redraw the histogram
+        paint();
+    }
+}

ch_16/exercise16_11/testFile.txt

@@ -0,0 +1,13 @@
+The jewelry store in Saratoga Springs where the first case was identified -- a man in his 60s -- has been closed since just before Christmas,
+it said. Gov. Andrew Cuomo has asked anyone who possibly may have been in contact with that man or even in contact with someone exposed to him to come forward.
+
+The man had not traveled recently, just like the man in the first identified U.S. case in Colorado, which suggests community spread has already happened.
+The CDC says the strain had been circulating in the U.K. since September, meaning it likely had been in the U.S. via
+travel for some time before it was detected in Colorado.
+
+Cuomo said Wednesday evidence appears to show the confirmed upstate case was connected to UK travel,
+despite no recent travel on behalf of the man.
+He called once again on the feds to mandate testing for all international travelers.
+Hospitals have become increasingly taxed over the last six weeks, a direct consequence of more infections from people's behavior,
+Cuomo has said. New York state hospitalizations are at 8,665, the same total admitted on May 6.
+Single-day death tolls are at mid-May levels. And weekly case averages are up 37 percent in New York over the past 14 days, according to New York Times data.

ch_16/exercise16_11/testFile2.txt

@@ -0,0 +1,3 @@
+aa 2
+bbb 3
+zzzz 4