Beginner Computer Programming

printing records of the linked list

runchman — Sun, 16 May 2010 03:52:21 +0000

I've posted a new video on printing the items in a linked list:
printing our linked list

Yahoo says become a software engineer

runchman — Thu, 13 May 2010 04:35:11 +0000

Yahoo today had an article "5 high-paying, low stress jobs". You can read the actual article here, but the paragraph below was what caught my eye. See, there's a reason to learn this programming stuff! The only drawback is that you get referred to as a 'tech geek'. Oh well.

Computer Software Engineer

If you're a tech geek seeking a relatively low-pressure career, you may want to check out the software engineering field. Software engineers design and test a variety of different types of software, from computer games to operating systems to business applications. These days, many software engineers can work from home, since their jobs can be done from practically anywhere.

Software engineers also bring home steep salaries, normally ranging between $54,000-130,000 a year. There's nothing nerdy about that.

linked list help

runchman — Thu, 13 May 2010 02:56:11 +0000

For more explanation of how to deal with adding records to a linked list, see the following videos:
adding a record to the head of a linked list
adding a record in the middle of the list
adding a record at the end of the list
These are all pretty basic, white-board type explanations. Nothing fancy - sometimes a simple explanation is just what you need.

finding a string within a string (a substring)

runchman — Fri, 07 May 2010 03:29:31 +0000

Suppose you want to search for a string within another string - for instance, you want to find if "house of pancakes" occurs anyplace within a string variable.

To do this, you use the function strstr (what I call "string string"). It's used as follows:

#include <string.h>

char * ptrToSubString;
char someTestString[100];

strcpy(someTestString,"welcome to joe's house of pancakes - we hope you have a great day");

ptrToSubString = strstr(someTestString,"house of pancakes");

// now if that pointer to the substring is NOT null, then we've found our substring.
// Let's check it out:
if (ptrToSubString != NULL) {
    printf("We found the string: %s\n",ptrToSubString);
}
else {
    printf("No pancakes have been found, we're so sorry\n");
}

And what will be printed in this case is:

We found the string: house of pancakes - we hope you have a great day

Notice that strstr just finds the BEGINNING POINT of the substring you are looking for - it doesn't do anything WITH the string it finds.

So the pointer that is returned points to the location where your substring begins - so when you print what that string points to, the string still ends where the original one did - at the terminating null character.

Simple enough.

how to use strcat to join 2 strings

runchman — Tue, 04 May 2010 03:35:28 +0000

Suppose you want to take a string and add it onto the end of another string.

For example, you have 2 strings, "abcd" and "efgh", and you want to join them into one string, "abcdefgh".

The function you use for this is strcat(string1,string2). It takes string2 and appends it onto the end of string1.

Consider the following sample code:

    char str1[1000];
    char * str2 = "test of strcat";

    strcpy(str1,"this is a ");
    strcat(str1,str2);

    printf("Result: %s\n",str1);

What is going on here?

First off we are allocating space for the first string, 1000 characters max.

Next, we define another string, str2, using a character pointer to a constant string, "test of strcat".

We initialize str1 using the string copy function, strcpy.

At this point str1 contains the string 'this is a '. The last character is the null character at position 10, after the 'a' and the final space.

Finally we get to our string concatenation function, strcat.

Strcat starts at the null at position 10, and replaces it with the first 't' in "test of strcat".

It continues putting characters in the array until it gets to the end of " of strcat", at which point it puts a terminating null after the 't', marking the new end of the string.

IMPORTANT NOTE: The original string, the first parameter in the strcat() function, must be large enough to contain the final string. If I had allocated the original string to be 10 characters, the strcat might cause a run-time error (segmentation fault), as the program attempts to write past the end of the array.

What does a software guy do all day?

runchman — Sun, 25 Apr 2010 04:32:49 +0000

Just what does a software guy, or computer programmer, actually do during a typical day at work?

In short, it depends.

It depends on what industry the programmer is in.

It depends on what stage of his or her career the programmer is at.

It depends on what project is going on, and what stage the project is going through.

It depends on how motivated the engineer is on that particular day.

So what gets done on a typical day? Could be just about anything. If you are just starting out, your focus, or sphere of influence, is probably small. You're probably concentrating on solving a small, individual problem. Perhaps there is a project in the works and you are coding up a small piece of it. You most likely aren't using much creative thought yet - problems of architecture, like how this big project is going to be constructed, aren't your concern. More senior members have figured that out already, and a small piece of the whole picture has been allocated to you.

If you are just starting out, you aren't yet aware of the glacial pace that most companies move. It can be amazing how little gets done on any given day.

And what type of work do you do? Maybe you work on embedded software, code that runs inside an engine controller or a cell phone. Or maybe you are writing application software, like something that runs on a clients laptop. If you are new and unlucky, maybe your company is making you start by just doing documentation, and little 'real' work. Creating documentation, while supposedly important, sucks. At least I think it does, maybe because I'm jut not motivated to do it.

One thing with software, is that many managers don't necessarily understand what is involved in creating it. This can be good or bad - they can think it should be easier than it is, and expect you to be more productive. Or on the flip side, they can have no clue how long something should take, and you can get away with cruising the web for 80% of your time if you like while you occasionally make progress on what you are 'supposed' to be doing.

But if I had to sum up in one line what a software engineer does on a daily basis, it is this:

A software engineer solves problems.

That's it. You are a problem solver. One thing to realize is that there is very little totally 'new' development that you will be doing. It's more likely you will be either figuring out why something is broken, or figuring out how something works so you can modify it or add functionality to it. Because of this, much of your time is spent reverse engineering how someone else's code works. You could refer to the documentation, but of course there probably isn't any.

So if you enjoy a challenge, like to think and solve problems, then software engineering is right up your alley.

The C ternary operator

runchman — Sun, 25 Apr 2010 04:06:56 +0000

The C ternary operator is a statement that allows you to put an "if..then..else" construct all on one line. It looks something like this:

x > 5 ? x+=1 : x-=1;

Let's break down what this does. The statement in general terms looks like this:

conditional ? true_operator : false_operator;

And if expanded out to its equivalent statement is:

if (conditional) {
    true_operator;
}
else {
    false_operator;
}

So our first example above is equivalent to this:

if ( x > 5 ) {
    x += 1;
}
else {
    x -= 1;
}

and remember that x+=1 is the same as x = x + 1, and x-=1 is the same as x = x - 1.

I like this operator. It's nice and compact, and I find it pleasing to the eye for some reason.

The Ternary operator. Next time you have an if-else, consider using it instead.

7 keys to learning programming

runchman — Sun, 18 Apr 2010 04:13:20 +0000

Consider these 7 keys to following through on your plan to learn programming:

1. Take it one step at a time - As the saying goes, Rome wasn't built in a day. No, you aren't building Rome. But programming isn't trivial. Give yourself permission for it to take some time. Nothing worthwhile - a successful marriage, well-raised kids, to mention two - is easy. But worth it, yes.

2. Become action oriented - This is a key in getting anything accomplished. I'm convinced this is the biggest thing that separates those that are 'lucky' from those that are struggling or are merely mediocre. Those that are going nowhere spend time talking about how 'lucky' those few are who have 'made it'. Well guess what, those successful people who have 'made it' worked hard to get there. Sit on your ass, and you'll get what that brings - a bigger rear end and a smaller bank account. Get off your butt and strive for something, work toward something, and then you'll become one of those 'lucky' people too. Funny how that works.

3. Learn how things really work under the surface - Don't just learn how to do something. Learn the why behind it. Then you'll have true understanding.

4. Don't sell yourself short - We all have our personal strengths and weaknesses, our pluses and minuses. But even those at the top, the people running the major corporations, are at their core just schmuks like me and you. In fact looking at how giant companies in the U.S. have imploded recently, I think you and I would have done a better job in that position. So don't sell yourself short. Believe you can do just as much as anyone else, because you truly can.

5. You hate strings in C. Yeah, we all do - Dealing with strings in C is a pain-in-the-butt. You know it, I know it, we all know it. But if you get good at understanding what is going on with strings deep down, your 'programming brain' development will definitely be well on its way.

6. Always be thinking about building blocks, and how you can restructure your code to be better - So, so often at work I run into code that has been around forever, and has just grown over time into a jumbled mess. Nobody has every stepped back, evaluated how things could be better structured, and changed things around. Always be thinking about your project from the 30,000 foot view. The more you think about how you could better meld your project into a cleaner design, the longer it will endure and the easier it will be to maintain.

7. Realize you will never know it all - especially as you get older, the pace of change becomes overwhelming. Make your peace with not 'knowing it all'. You never will. There will be languages and technologies you only know in passing. This is a good thing - it means if you ever get bored, there is still a lifetime of learning out there available to you.

Keep at it, relentlessly. You're success is inevitable.

programming course

runchman — Thu, 15 Apr 2010 01:44:07 +0000

What are some of the things you'll learn in my computer programming course?

Variables - things in computer code that hold values

Control flow - how your program changes direction depending on what happens

Looping - various ways to do things a bunch of times when your program requires it.

file input / output - how to read and write to files on your computer

Architecture - how to structure your program, or build it so it is maintainable and understandable

Debugging - how to figure out what is going wrong with your program.

Syntax - the details of exactly how each element of the programming language is used.

And everything else you need to learn to become a good programmer.

So get started if you want to move forward with your skill !

Sounds like a good journey, right?

Video, but not the Video Professor

runchman — Tue, 13 Apr 2010 19:17:09 +0000

A few of the friends that I've mentioned my instructional website to have commented "Oh yeah, like that video... that video guy....", to which I respond "Yeah, that video professor guy, right, kind of like that."

Except not like that at all.

From what I've read, his business model is to get you to buy a product, and then to make it very challenging for you to either cancel your subscription, or to get your money back if you aren't satisfied.

Now for a disclaimer: I've never purchased any of his products. They may well be excellent quality, for all I know. Any negative reviews online might just be sour grapes.

But my business model is not like that. The last thing I want to do is to deceive anyone, or to have someone feel they got ripped off by me. My model is to engage the person who wants to learn programming, to build a relationship with the student, and to hope they feel they get enough value out of a personal-interaction model that they decide to sign up for a membership.

I want you to be fully satisfied with what you get out of my instruction, regardless of how long you've had access to my material, or how much of it you have taken advantage of. I'd be extremely upset if I ever saw a negative review of my business practices online. You can think my product sucks, that my teaching is horrible, and that is fine. But you will never have reason to post that you feel you didn't get your money's worth out of my site, because if anyone ever feels that, I will gladly refund any money they've paid to me.

And none of this nonsense about 'full refund, minus shipping and handling'. No, full refund means just that: full refund.

So yes, I have videos. And I suppose you could jokingly refer to me as a professor. But another video professor? I don't think so.