A202/A597 Introduction to Programming I (4/3 cr.)

CSCI A201/A597
Lecture Notes 6

Spring 2000

Wrapping up Homework 1 Notes. Selecting and reporting the maximum value from a sequence of values. Command-line arguments. Introduction to the lab notes and to the element package.

Today we will discuss the following program:

public class FindMax {
    public static void main(String[] args) {
	int size = args.length; 
        int max = 0; 
	for (int i = 0; i < size; i++) { 
	    int number = Integer.parseInt(args[i]); 
            if (number > max) {
		max = number; 
	    } 
	}
	System.out.println("Max is: " + max); 
    }
}

The goal is to understand completely all of the elements that appear in this program, as well as how it works. Consider the following questions:

What is the program computing and how do you run/use it?
How can you make it compute the minimum rather than the maximum?
How can you make it report both the index and the value of it?
How can you make the program sum up the numbers on the command line?
How can you make the program produce an average of the numbers on the command line where the lowest argument is dropped?
What do you do when the user types no arguments?
How do you write this program using a while loop?

The answers to these questions are all simple variations on the program above. In class we will develop solutions (programs) for these questions. I will add the code that we will develop in class to these lecture notes after the class.

We are going to introduce a new primitive type in the process, to be able to compute with decimals, called double.

This should be wrapping up the notes for the homework assignment.

Next we will discuss the lab assignment (In-Lab #2). You will have to write a program and test several others that make use of the package (element) that is described in Chapter 2 of your text. Here now is a description of the program that you need to write.

See lab 3 notes for more details on that. In class I will only demo a prototype and take any questions that you may have.

Finally you will have to test a few programs on the floppies that will be distributed to you in the labs (which contain the packages that we need for this class). The programs will be demoed in class today. In lab we just want to make sure that you can use the packages distributed to you and for this part of the in-lab assignment you should turn in both the source code as well as the .class files.

See lab notes 3 for more details and the source code of the programs.

As mentioned the goal is to experiment with the programs and get exposed to the way they receive input and produce output. Next week we will try to understand them very well so that we can write other programs similar to them, or to enhance these very programs (making them more robust, or adding new functionality).

Last updated: January 27, 2000 by Adrian German

CSCI A201/A597 Lecture Notes 6

CSCI A201/A597
Lecture Notes 6