computer programming tutorial

computer programming basic

 

Today, most people don't need to know how a computer works.  Most people can simply turn on a computer or a mobile phone and point at some little graphical object on the display, click a button or swipe a finger or two, and the computer does something.  An example would be to get weather information from the net and display it.  How to interact with a computer program is all the average person needs to know.
But, since you are going to learn how to write computer programs, you need to know a little bit about how a computer works.  Your job will be to instruct the computer to do things.

 
  Basically, writing software (computer programs) involves describing processes, procedures; it involves the authoring of algorithms. Computer programming involves developing lists of instructions - the source code representation of software  The stuff that these instructions manipulate are different types of objects, e.g., numbers, words, images, sounds, etc...  Creating a computer program can be like composing music, like designing a house, like creating lots of stuff.  It has been argued that in its current state it is an art, not engineering.
An important reason to consider learning about how to program a computer is that the concepts underlying this will be valuable to you, regardless of whether or not you go on to make a career out of it.  One thing that you will learn quickly is that a computer is very dumb, but obedient.  It does exactly what you tell it to do, which is not necessarily what you wanted.  Programming will help you learn the importance of clarity of expression.

    A deep understanding of programming, in particular the
    notions of successive decomposition as a mode of analysis
    and debugging of trial solutions, results in significant
    educational benefits in many domains of discourse,
    including those unrelated to computers and information
    technology per .
                            
    It has often been said that a person does not really
    understand something until he teaches it to someone else.
    Actually a person does not really understand something
    until after teaching it to a computer, i.e., express it
    as an algorithm.
           

    Computers have proven immensely effective as aids to clear
    thinking.  Muddled and half-baked ideas have sometimes
    survived for centuries because luminaries have deluded
    themselves as much as their followers or because lesser
    lights, fearing ridicule, couldn't summon up the nerve to
    admit that they didn't know what the Master was talking
    about. A test as near foolproof as one could get of whether
    you understand something as well as you think is to express
    it as a computer program and then see if the program does
    what it is supposed to. Computers are not sycophants and
    won't make enthusiastic noises to ensure their promotion
    or camouflage what they don't know.  What you get is what
    you said.
              
           
But, most of all, it can be lots of fun!  An associate once said to me "I can't believe I'm paid so well for something I love to do."
Just what do instructions a computer understands look like?  And, what kinds of objects do the instructions manipulate?  By the end of this lesson you will be able to answer these questions.  But first let's try to write a program in the English language.
PROGRAMMING USING THE ENGLISH LANGUAGE
Remember what I said in the Introduction to this lesson?
           
      Writing software, computer programs, is a lot like
      writing down the steps it takes to do something.
                 
Before we see what a computer programming language looks like, let's use the English language to describe how to do something as a series of steps.  A common exercise that really gets you thinking about what computer programming can be like is to describe a process you are familiar with.
      Describe how to make a peanut butter and jelly sandwich.
           
Rather than write my own version of this exercise, I searched the Internet for the words "computer programming sandwich" using Google.  One of the hits returned was http://teachers.net/lessons/posts/2166.html.  At the link, Deb Sweeney  described the problem as:

      Objective: Students will write specific and sequential steps
         on how to make a peanut butter and jelly sandwich.

      Procedure: Students will write a very detailed and step-by-step
         paragraph on how to make a peanut butter and jelly
         sandwich for homework. The next day, the students will
         then input (read) their instructions to the computer
         (teacher). The teacher will then "make" the programs,
         being sure to do exactly what the students said...
           
When this exercise is directed by an experienced teacher or mentor it is excellent for demonstrating how careful you need to be, how detailed you need to be, when writing a computer program.  Here is teacher/mentor support material.
Programming in a natural language, say the full scope of the English language, seems like a very difficult task.  But, before moving on to languages we can write programs in today, I want to leave on a high note.  Click here to read about how Stephen Wolfram sees programming in a natural language happening.