Question

Prelab Exercises
Your task is to write a Java program that will print out the following message (including the row of equal marks):
Computer Science, Yes!!!!
=========================
An outline of the program is below. Complete it as follows:
a. In the documentation at the top, fill in the name of the file the program would be saved in and a brief description of what
the program does.
b. Add the code for the main method to do the printing.
// ************************************************************
// File Name:
//
// Purpose:
// ************************************************************
public class CSYes
{
// -------------------------------------------------
// The following main method prints an exciting
// message about computer science
// -------------------------------------------------
}

Comments
File Count.java contains a Java program that counts from 1 to 5 in English, French, and Spanish. Save this file to your
directory and compile and run it to see what it does. Then modify it as follows:
1. Use // style comments to add a comment header at the top of the file that includes the name of the program, your name,
and a brief description of what the program does, neatly formatted. Include a delimiter line (e.g., all stars) at the
beginning and end of the header.
2. Add a comment before each println that indicates what language the next line is in. Experiment with leaving a blank line
before each of these comment lines (in the program itself, not the output). Is the program easier to read with or without
these blank lines?
3. Remove one of the slashes from one of your comment lines and recompile the program, so one of the comments starts
with a single /. What error do you get? Put the slash back in.
4. Try putting a comment within a comment, so that a // appears after the initial // on a comment line. Does this cause
problems?
5. Consult the documentation guidelines in Appendix F of the text. Have you violated any of them? List two things that you
could imagine yourself or someone else doing in commenting this program that these guidelines discourage.
Count.java
public class Count
{
public static void main (String[] args)
{
System.out.println ("one two three four five");
System.out.println ("un deux trois quatre cinq");
System.out.println ("uno dos tres cuatro cinco");
}
}

Correcting Syntax Errors
File Problems.java contains a simple Java program that contains a number of syntax errors. Save the program to your
directory, study it and correct as many of the errors as you can find. Then compile the program; if there are still errors,
correct them. Some things to remember:

Java is case sensitive, so, for example, the identifiers public, Public, and PUBLIC are all considered different. For
reserved words such as public and void and previously defined identifiers such as String and System, you have to get the
case right. You will learn the conventions about case soon, but for now you can look at a sample program in the text to
see what case should be used where.

When the compiler lists lots of errors, fix the first one (or few) and then recompile—often the later errors aren’t really
errors in the program, they just indicate that the compiler is confused from earlier errors.

Read the error messages carefully, and note what line numbers they refer to. Often the messages are helpful, but even
when they aren’t, the line numbers usually are.

When the program compiles cleanly, run it.
// ********************************************
// Problems.java
//
// Provide lots of syntax errors for the user to correct.
//
********************************************
public class problems
{
public Static main (string[] args)
{
System.out.println ("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
System.out.println ("This program used to have lots of problems,");
System.out.println ("but if it prints this, you fixed them all.")
System.out.println (" *** Hurray! ***");
System.out.println ("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
}

Answer 1

Prelab Exercise:

CSYes.java

// ************************************************************

// File Name: CSYes.java
// Author Name: Your name here.
// Purpose: To print Computer Science, Yes!!!!
// ************************************************************
public class CSYes
{
// -------------------------------------------------
// The following main method prints an exciting
// message about computer science
// -------------------------------------------------

public static void main(String[] args){

System.out.println("Computer Science, Yes!!!!");

}
}

Comments:

Count.java

// ************************************************************

// File Name: Count.java
//Author name: Your name here.
// Purpose: To count the subjects in different langauge.
// ************************************************************

public class Count
{
public static void main (String[] args)
{

//This print statement prints count in English.  
System.out.println ("one two three four five");

//This print statement prints count in French.

System.out.println ("un deux trois quatre cinq");

// This print statement prints count in Spanish.

System.out.println ("uno dos tres cuatro cinco");
}
}

3. If we remove one slash from the comment, the compiler throws the below error

Syntax error on token "/", delete this token.

after putting the slash back, code runs fine with no compilation error.

4. Comment within a comment for eg. //hi i am // subrat works fine without compilation error.

5. Appendix F is not given so hard to tell, if we have violated any.

Correcting Syntax Errors

Corrected Problems.java code is below

// ********************************************
// Problems.java
// Author: Your Name here.
// Description: Provide lots of syntax errors for the user to correct.
//
********************************************
public class Problems //Class names should be nouns, in mixed case with the first letter of each internal word capitalized.
{
public static void main (String[] args) //static is a keyword it must be in small, and there should be a return type of main method and String is a class so first letter must be in uppercase
{
System.out.println ("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
System.out.println ("This program used to have lots of problems,");
System.out.println ("but if it prints this, you fixed them all."); //the statement must end with the ';'
System.out.println (" *** Hurray! ***");
System.out.println ("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
}

}//code mblock must be ended with'}' if a block is starting with '{' then must end with '}'