Question

Getting started with Java on elvis

Download Greeting.java from the class web site. Use FileZilla to place it into your Lab5 directory.

Look at the content of your directory to see the file using the command ls

Look at the content of the file in your directory using the command more Greeting.java

Compile the HelloClass program using the command javac Greeting.java. Then use ls to see your class file.

Run the program without parameters using the command java Greeting

Run the program a second time with two names as parameters.

Run the program a third time with the same two names, only this time use file indirection to send the output to file greeting.txt. What did you notice about System.in? Include greeting.txt in your lab submission.

Download and run Greeting2.java.

//Greeting.java

import java.util.Scanner;

/**
 * This is the first incarnation of Greeting.
 * It demonstrates how to pass arguments to main method
 * 
 * @author myersjac
 *
 */
public class Greeting {

        public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
                try { 
                String myName = args[0];
                String yourName = args[1];
                System.out.println("Are you sure you want to say hello to " + yourName+ "?");
                if (sc.nextLine().toLowerCase().equals("no")) {
                        System.out.println("Who would you rather say hello to?");
                        yourName = sc.next();
                }
                System.out.println(myName + " says hello to " + yourName);
        }
        catch (ArrayIndexOutOfBoundsException e) {
                System.out.println("Hello!");
        }
        finally {
                sc.close();
        }
    }
}

//Greeting2.java

import java.util.ArrayList;
import java.util.Scanner;

/**
 * This is the second incarnation of Greeting
 * It prompts for a number of people who will greet the class
 * 
 * @author myersjac
 *
 */
public class Greeting2 {

        public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter number of people: ");
        ArrayList<String> names = new ArrayList<String>();
        int numberOfPeople = Integer.parseInt(sc.nextLine());
        int i;
        for (i = 0; i < numberOfPeople; i++) {
                System.out.printf("Enter name #%d: ", i+1);
                names.add(sc.nextLine());
        }
        String nameString = "";
        for (String name : names) {
                nameString += name + ", ";
        }
        // Kill terminal ", "
        nameString = nameString.substring(0, nameString.lastIndexOf(","));
        // Get up to the last name
        nameString = nameString.substring(0, nameString.lastIndexOf(" ")) +
                             " and " + 
                             nameString.substring(nameString.lastIndexOf(" ")+1, nameString.length());
        System.out.println(nameString + (i==1 ? " says" : " say") + " Hello Class!!!");
        sc.close();
        }
}