Learning Modula2 through exercises: SOLUTIONS

Introduction

Learning to program in Modula2 is like learning to speak a new language. You will have to memorize a whole set of new words. Learn to understand what they mean so that you can use them at the right moment. Not forgetting that you have to be able to write them correctly (computers are very bad at understanding what you actually mean!).

But this is not enough! Programming is about using one such language to control a computer to solve your problems. Programming is to computer language what literature is to a language: the realisation of ones idea using the given tool (be it a computer or human language).

Approach

Each program serves as a basis for an exercise which requires your brain power. Yes, you will need to get your hands dirty to learn to program in Modula2. In other words, you will be reading, executing and modifiying programs all the time. And before you know it the brand new (programming) language will turn out to be quite readable actually. If and only if you put all your energy into making the exercises! Experience learn that reading the exercises is not enough!

Table of content

• Basic structure of a Modula2 program.
• Variables a way to make the computer remember!!!
• CONSTants can't be changed right?

• How you display things on the screen.
• Reading from the keyboard into your program.

• Working with INTEGERs in Modula2 as easy as 1 + 1.
• Scientific and engineering math using Modula2.
• Converting numbers: from 1 to 1.0 and back.

• We need Boolean algebra : TRUE or FALSE?
• Skip parts of a program using IF.
• Choose between alternatives

• Be lazy and learn how to say: "computer do this N times!"
• In Modula2 you can say :"computer work until I back".
• But you can also say :"while I am gone you work".
• Repeat forever with a LOOP.

• Using values like rain, sun and fog to reason within your programs.
• Limit the values a variable can have.

• Storing many values at once using ARRAYs.
• More complex arrays: 2D and more.

• Representing CHARacters in a Modula2 program.
• Print your name on the screen using character strings.

• Creating your own dataTYPEs, quite useful actually.
• Combining different kind of data into one.

• Write your own PROCEDURES to save yourself some time and work!
• Procedure can also work with arrays.
• Even more powerful procedures using VAR parameters.

• Scoping allows to structure your programs.
• Recursion : fun... but dangerous.

• Ouch, we need more memory.
• A generic pointer type.

• Simple graphics using the TopSpeed package

• Using the debugger

• Variant records : flexible data types

• Abstract Data Types : one step closer to clean programming
• Modules : why and how

• Procedure types
• Lookup tables
• Lazy evaluation
• Writing self testing code
• Practicum II demos