Added Java lab programs

2026-05-16 19:35:25 +00:00 · 2025-12-17 16:36:20 +05:30
parent ac2904f5db
commit 2f4beade3b
46 changed files with 882 additions and 0 deletions
@@ -0,0 +1,121 @@
+import java.util.Scanner;
+
+// -------- Helper Class --------
+class TextHelper {
+
+    private String text;
+    private String keyword;
+
+    TextHelper(String text, String keyword) {
+        this.text = text;
+        this.keyword = keyword;
+    }
+
+    // 1. View character at a position
+    void viewCharacter(int position) {
+        if (position >= 0 && position < text.length()) {
+            System.out.println(
+                "Character at position " +
+                    position +
+                    ": " +
+                    text.charAt(position)
+            );
+        } else {
+            System.out.println("Invalid position!");
+        }
+    }
+
+    // 2. Compare text and keyword
+    void compareText() {
+        int result = text.compareTo(keyword);
+
+        if (result == 0) System.out.println("Text and keyword are equal.");
+        else if (result < 0) System.out.println(
+            "Text comes before keyword alphabetically."
+        );
+        else System.out.println("Keyword comes before text alphabetically.");
+    }
+
+    // 3. Search & replace keyword
+    void searchAndReplace(String replacement) {
+        int index = text.indexOf(keyword);
+
+        if (index == -1) {
+            System.out.println("Keyword not found in text.");
+        } else {
+            System.out.println("Keyword first found at position: " + index);
+            text = text.replace(keyword, replacement);
+            System.out.println("Updated Text: " + text);
+        }
+    }
+
+    // 4. Extract substring
+    void extractPortion(int start, int end) {
+        if (start >= 0 && end <= text.length() && start < end) {
+            System.out.println("Extracted Text: " + text.substring(start, end));
+        } else {
+            System.out.println("Invalid start or end position!");
+        }
+    }
+}
+
+// -------- Main Class --------
+public class TextProcessingHelper {
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+
+        System.out.print("Enter main text: ");
+        String text = sc.nextLine();
+
+        System.out.print("Enter keyword: ");
+        String keyword = sc.nextLine();
+
+        TextHelper helper = new TextHelper(text, keyword);
+
+        int choice;
+
+        do {
+            System.out.println("\n--- Text Processing Menu ---");
+            System.out.println("1. View character at a position");
+            System.out.println("2. Compare text and keyword");
+            System.out.println("3. Search and replace keyword");
+            System.out.println("4. Extract portion of text");
+            System.out.println("5. Exit");
+            System.out.print("Enter your choice: ");
+
+            choice = sc.nextInt();
+            sc.nextLine(); // consume newline
+
+            switch (choice) {
+                case 1:
+                    System.out.print("Enter position: ");
+                    int pos = sc.nextInt();
+                    helper.viewCharacter(pos);
+                    break;
+                case 2:
+                    helper.compareText();
+                    break;
+                case 3:
+                    System.out.print("Enter replacement word: ");
+                    String replacement = sc.nextLine();
+                    helper.searchAndReplace(replacement);
+                    break;
+                case 4:
+                    System.out.print("Enter start position: ");
+                    int start = sc.nextInt();
+                    System.out.print("Enter end position: ");
+                    int end = sc.nextInt();
+                    helper.extractPortion(start, end);
+                    break;
+                case 5:
+                    System.out.println("Exiting program...");
+                    break;
+                default:
+                    System.out.println("Invalid choice!");
+            }
+        } while (choice != 5);
+
+        sc.close();
+    }
+}