Project: Flashcards

src/flashcards/Flashcards.java

@@ -0,0 +1,98 @@
+package flashcards;
+import java.util.*;
+import java.io.*;
+//class for create cards. behavior; add,ask,remove,import,export
+
+class Flashcards {
+    private Scanner scanner = new Scanner(System.in);
+    private Map<String, String> cardToDefinition = new HashMap<>();
+    private Map<String, String> definitionToCard = new HashMap<>();
+
+    //add cards and definition
+    void add() {
+        System.out.println("The card:");
+        String userCard = scanner.next();
+        System.out.println("The definition of the card");
+        String userDefinition = scanner.next();
+        if (cardToDefinition.containsKey(userCard) || cardToDefinition.containsValue(userDefinition)) {
+            System.out.println("Don't use a duplicated card or a definition");
+        } else {
+            cardToDefinition.put(userCard, userDefinition);
+            definitionToCard.put(userDefinition, userCard);
+            System.out.println("The pair (" + userCard + ":" +userDefinition + ") is added.");
+        }
+    }
+
+    //asking user and checking it
+    void ask() {
+        System.out.println("How many times to ask?");
+        int numOfAsk = scanner.nextInt();
+        for (Map.Entry<String, String> card : cardToDefinition.entrySet()) {
+            System.out.println("Print the definition of (" + card.getKey() + "):");
+            String answer = scanner.next();
+            if (answer.equals(card.getValue())) {
+                System.out.print("Correct answer.");
+            } else if (cardToDefinition.containsValue(answer)) {
+                // If the definition is wrong but it is presented in another card
+                System.out.print("Wrong answer (the correct one is " + card.getValue()+ ", you've just written a definition of " + definitionToCard.get(answer) + " card).");
+            } else {
+                System.out.print("Wrong answer (the correct one is " + card.getValue() + ").");
+            }
+            if (--numOfAsk==0) {
+                break;
+            }
+        }
+    }
+
+    //remove card
+    void remove() {
+        System.out.println("The card:");
+        String userCard = scanner.nextLine();
+        if (cardToDefinition.containsKey(userCard)) {
+            definitionToCard.remove(cardToDefinition.get(userCard));
+            cardToDefinition.remove(userCard);
+            System.out.println("(" + userCard + ") removed.");
+        } else {
+            System.out.println("Can't remove (" +userCard + "): there is no such card.");
+        }
+    }
+
+
+    // import cards from txt
+    void importCards() {
+        String pathToFile = "E:/_LearnProgramming/IdeaProjects/flashcards/capitals.txt";
+        File file = new File(pathToFile);
+        int counter=0;
+        try (Scanner reader = new Scanner(file)) {
+            while (reader.hasNext()) {
+                String userCard = reader.next();
+                String userDefinition = reader.next();
+                counter++;
+                if (cardToDefinition.containsKey(userCard) || cardToDefinition.containsValue(userDefinition)) {
+                    System.out.println("Don't use a duplicated card or a definition");
+                    counter--;
+                } else {
+                    cardToDefinition.put(userCard, userDefinition);
+                    definitionToCard.put(userDefinition, userCard);
+                }
+            }
+            System.out.println(counter + " cards have been loaded.");
+        } catch (FileNotFoundException e) {
+            System.out.println("No file found: " + pathToFile);
+        }
+    }
+
+    void exportCards() {
+        String pathToFile = "E:/_LearnProgramming/IdeaProjects/flashcards/capitals_export.txt";
+        File file = new File(pathToFile);
+        try (PrintWriter printWriter = new PrintWriter(file)) {
+            for (Map.Entry<String, String> card : cardToDefinition.entrySet()) {
+                printWriter.println(card.getKey());
+                printWriter.println(card.getValue());
+            }
+            System.out.println(cardToDefinition.size() + " cards have been saved.");
+        } catch (IOException e) {
+            System.out.printf("An exception occurs %s", e.getMessage());
+        }
+    }
+}

src/flashcards/Main.java

@@ -1,7 +1,59 @@
-package flashcards;
+/*
+Stage 4: There is a common situation that the answer is wrong for the given card but it's correct for another card. Let's consider situations like this.
+Remove array-based storage. Use two maps (Map<String, String>): cardToDefinition and definitionToCard. If the definition is wrong but it is presented
+in definitionToCard, output the original card.
+When the user tries to add a duplicated card or a definition, forbid it. For now you are able to implement this without a try catch construction.
+Use the rule: if you can avoid exception-based logic, avoid it!
+
+Stage 5: Improve the application’s interactivity. Ask the user for an action and do it.
+Support these actions:
+add a card: add,
+remove a card: remove,
+load cards from file ("deserialization"): import,
+save cards to file ("serialization"): export,
+ask for definition of some random cards: ask,
+exit the program: exit.
+You can use the following file format. The file consists of pairs of lines. The first line of each pair is a card, and the second line is a definition of the card.
+ */
 
+package flashcards;
+import java.util.*;
 public class Main {
     public static void main(String[] args) {
-        System.out.print("Hello world!");
+        usingFlashcards();
+    }
+
+    private static void usingFlashcards() {
+        Scanner scanner = new Scanner(System.in);
+        Flashcards flashcards = new Flashcards();
+        String action;
+        do {
+            System.out.println("Input the action (add, remove, import, export, ask, exit):");
+            action = scanner.next();
+            switch (action) {
+                case "add":
+                    flashcards.add();
+                    break;
+                case "remove":
+                    flashcards.remove();
+                    break;
+                case "ask":
+                    flashcards.ask();
+                    break;
+                case "import":
+                    flashcards.importCards();
+                    break;
+                case "export":
+                    flashcards.exportCards();
+                    break;
+                case "exit":
+                    break;
+                default:
+                    System.out.println("Wrong action!");
+                    break;
+            }
+        } while (!action.equals("exit"));
+        scanner.close();
+        System.out.println("Bye bye!");
     }
 }