StringManipulation.java

import java.util.Scanner;

public class StringManipulation {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter the first string:");
        String input1 = scanner.nextLine();
        char[] string1 = input1.toCharArray();
        // a) string length
        int length1 = stringLength(string1);
        System.out.println("Length of the first string:" + length1);
        // b) finding a character at a particular position
        System.out.println("Enter the position to find the character:");
        int position = scanner.nextInt();
        scanner.nextLine();
        if (position > 0 && position < length1) {
            char character = charAt(string1, position - 1);
            System.out.println("Character at position " + (position) + ":" + character);
        } else {
            System.out.println("Position out of bounds.");
        }
        System.out.println("Enter the second string:");
        String input2 = scanner.nextLine();
        char[] string2 = input2.toCharArray();
        // c) concatenating two strings
        char[] concatenatedString = concatenate(string1, string2);
        System.out.println("Concatenated String:" + new String(concatenatedString));
        scanner.close();
    }

    public static int stringLength(char[] string) {
        int length = 0;
        for (char c : string) {
            length++;
        }
        return length;
    }

    public static char charAt(char[] string, int position) {
        return string[position];
    }

    public static char[] concatenate(char[] string1, char[] string2) {
        int length1 = stringLength(string1);
        int length2 = stringLength(string2);
        char[] result = new char[length1 + length2];
        for (int i = 0; i < length1; i++) {
            result[i] = string1[i];
        }
        for (int i = 0; i < length2; i++) {
            result[length1 + i] = string2[i];
        }
        return result;
    }
}