OOPS-lab-codes/TextProcessingHelper.java

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();
    }
}