1. About this course

Prerequisites:

This course assumes two semesters of prior programming coursework in a programming language such as Java, Python, C++ or other languages. If your experience is in older languages such as C, or Pascal, you will have some difficulty, and if your experience is largely in ancient languages such as BASIC, COBOL, or FORTRAN, you will really need to work hard.

From the first programming course, you should have learned the basics of programming. How to write programs involving loops, if-then-else constructs, and function calls. You should be comfortable with simple variables, arrays and perhaps the outside view of several container classes such as lists or sets.

From the second programming course, you should have learned something about data structures and algorithms. Lists, queues, binary search, lexicographic trees, sorting, and several recursive algorithms. The formal analysis of algorithms is a more advanced topic, but you should have seen enough to develop an intuition for the fact that some algorithms are potentially much faster than others when used to achieve the same goal. Consider for example the difference between binary search and linear search, or the difference between quicksort and bubble sort.

In general, programming assignments in those introductory courses are short, rarely amounting to more than a few hundred lines of code, and frequently under 50 lines of code. (Yes, the "line of code" is a horrible way to measure program size, since any program can be converted, with very little effort, into a larger, harder to read and yet functionally identical program.)

Goals:

Previous offerings of this course have used several different languages, but what matters is, this is not a course about a specific programming language. You know how to program, and learning the syntax of a new language is not all that hard.

It is noteworthy that the programming languages you are likely to have learned in any intro course taught in the last 20 years all support object oriented development, but the small programming assignments you had in your intro courses are unlikely to do more than use built-in classes, and in a second semester course, while you may have implemented a new class, you didn't really need to do so except that it was assigned. This is a natural consequence of small programming assignments.

The need for something like object oriented programming is not apparent until you get into large problems. Try to write a digital logic simulator capable of simulating a complete CPU at the level of and, or and not gates. Try to write a compiler, try to write a spreadsheet package, or any of many other large applications, and you will find that the story is quite different. If object oriented programming had not been developed already, you would be very likely to re-invent it working with problems on that scale.

This course, therefore asks you to work through a large programming project, large enough that you really need to use objects. Programming in the large will ask for more than objects, it also requires management, documentation and methodology.

When you write small programs, who needs documentation? Here is an example, written in the old C programming language. The fact that you might not know C should not matter to your understanding of this code:

	int add( int a, int b ) {
		return a + b;
	}

If you don't know C, you might need someone to explain that int is a data type and that declarations in C put the type name before the object being declared, but with this, you should be able to guess that the function call add(1,2) will return 3. Adding comments or writing a page of text to document this code serves little purpose. Is the following code any easier to read?

	int add( int a, int b ) {
                /* function to add two numbers a and b
                 * prerequisites: parameters a and b are integers
                 * return value: an integer, the sum of a and b
                 * side effects:  none
                 */

		/* compute the integer sum of a and b */
		int result = a + b;

		/* return the resulting value */
		return result;
	}

The story is quite different when your program is 5000 lines long. At that point, you can't grasp the whole thing at a glance, and you are unlikely to be able to remember from one day to the next what each part of the program does. When programs get that big, you need documentation even if there is only one programmer, and when there is a team involved, documentation becomes even more important.

In summary, this is a course about programming in the large, where up to this point, you have been programming in the small.

A Public Service Announcement:

Most of the best Co-Op internships for next summer were filled in the fall, but there are still occasional opportunities. If you are looking for summer jobs, get yourself into the pipeline both at the Business and Liberal Arts placement office and at the the Engineering placement office. CS students are welcome at career fairs sponsored by both placement offices.