public class Sample09 {
    public static void main(String[] args) {
        String txt = "HelloWorld";
        System.out.println("The length of the txt string is:" + txt.length());

        System.out.println(txt.toUpperCase());
        System.out.println(txt.toLowerCase());

        System.out.println(txt.indexOf("World"));

        String firstName = "Chen";
        String lastName = "Haipeng";
        System.out.println(firstName + " " + lastName);
        System.out.println(firstName.concat(lastName));

        String txt1 = "We are the so-called \"Vikings\" from the north.";
        String txt2 = "It\'s alright";
        String txt3 = "The character \\ is called backslash.";
        System.out.println(txt1);
        System.out.println(txt2);
        System.out.println(txt3);
    }
}