feat: today's practice implemented

src/main/java/me/alex4386/gachon/sw14462/Main.java

@@ -5,7 +5,7 @@
 import java.util.*;
 
 public class Main {
-    public static String currentTarget = "day22";
+    public static String currentTarget = "day23";
     public static boolean fallbackToLatest = true;
 
     public static Map<String, Class<?>> getAvailableTargetClassNames() {

src/main/java/me/alex4386/gachon/sw14462/day23/Main.java

@@ -0,0 +1,18 @@
+package me.alex4386.gachon.sw14462.day23;
+
+import me.alex4386.gachon.sw14462.utils.Chainloader;
+
+public class Main {
+    public static String chainloadTarget = "ex13_1b";
+
+    public static void main(String[] args) throws Throwable {
+        String packageName = Main.class.getPackage().getName();
+        String chainLoadTargetClass = packageName + "." + chainloadTarget + ".Main";
+
+        try {
+            Chainloader.chainloadTarget(chainLoadTargetClass, args);
+        } catch (Exception e) {
+            throw e;
+        }
+    }
+}

src/main/java/me/alex4386/gachon/sw14462/day23/ex13_1a/Main.java

@@ -0,0 +1,97 @@
+package me.alex4386.gachon.sw14462.day23.ex13_1a;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        System.out.print("Enter the filename: ");
+        String filename = scanner.nextLine();
+
+        // generate 10 random integer
+        int[] randomIntegers = new int[10];
+        for (int i = 0; i < 10; i++) {
+            randomIntegers[i] = (int) (Math.random() * 1000);
+        }
+
+        // write to file
+        File targetFile = new File(filename);
+        if (targetFile.exists()) {
+            // unlink the file
+            targetFile.delete();
+        }
+
+        FileOutputStream stream;
+        try {
+            targetFile.createNewFile();
+            stream = new FileOutputStream(targetFile);
+        } catch (Exception e) {
+            System.err.println("Failed to create file: " + e.getMessage());
+            return;
+        }
+
+        PrintWriter writer = new PrintWriter(stream);
+        for (int i = 0; i < 10; i++) {
+            writer.println(randomIntegers[i]);
+        }
+
+        writer.close();
+        System.out.println("File created successfully.");
+
+        scanner.close();
+
+        // reopen the file
+        targetFile = new File(filename);
+        if (!targetFile.exists()) {
+            System.err.println("File does not exists, is the file has been deleted in the meantime?");
+            return;
+        }
+
+        try {
+            scanner = new Scanner(targetFile);
+        } catch (Exception e) {
+            System.err.println("Failed to open file: " + e.getMessage());
+            return;
+        }
+
+        int count = 0;
+        int min = Integer.MAX_VALUE, max = Integer.MIN_VALUE, sum = 0;
+        double average;
+
+        List<Integer> integers = new ArrayList<>();
+        while (scanner.hasNextLine()) {
+            String content = scanner.nextLine();
+            if (content.trim().equals("")) continue;
+
+            int value = 0;
+            try {
+                value = Integer.parseInt(content);
+            } catch (NumberFormatException e) {
+                System.err.println("Invalid number: " + e.getMessage());
+                continue;
+            }
+
+            integers.add(value);
+            count++;
+            sum += value;
+            if (value < min) min = value;
+            if (value > max) max = value;
+        }
+
+        average = (double) sum / count;
+        scanner.close();
+
+
+        System.out.println("min: "+min);
+        System.out.println("max: "+max);
+        System.out.println("sum: "+sum);
+        System.out.println("average: "+average);
+
+    }
+}

src/main/java/me/alex4386/gachon/sw14462/day23/ex13_1b/Main.java

@@ -0,0 +1,43 @@
+package me.alex4386.gachon.sw14462.day23.ex13_1b;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        String targetFilename = "names.txt";
+        String firstNameCache = "";
+
+        File file = new File(targetFilename);
+        if (!file.exists()) {
+            System.err.println("File not found: " + targetFilename);
+            System.exit(1);
+        }
+
+        Scanner scanner;
+        try {
+            scanner = new Scanner(file);
+        } catch (FileNotFoundException e) {
+            System.err.println("File not found: " + e.getMessage());
+            System.exit(1);
+            return;
+        }
+
+        while (scanner.hasNextLine()) {
+            String line = scanner.nextLine();
+            String[] names = line.split(" ");
+
+            for (int i = 0; i < names.length; i++) {
+                if (firstNameCache.equals("")) {
+                    firstNameCache = names[i];
+                } else {
+                    System.out.println(firstNameCache + " " + names[i]);
+                    firstNameCache = "";
+                }
+            }
+        }
+
+        scanner.close();
+    }
+}