How To: Beginner Programming: Part 2 - Primitive Variables and Arithmetic

Hello, and welcome to How To: Beginner Programming,

a multi-part guide to your first steps into the world of programming.

In each of the following episodes, I'll be demonstrating the
basic principles of programming,

from creating your first application, to developing your own objects.

In the previous episode, we talked about Hello World,

setting up your environment, and outputting text to the screen.

In this episode I'll be explaining what variables are,

the types of variables available for use,

and some arithmetic that can be performed on them.

Right here I've got all the types of primitive variables...

These are all variables; the most basic types of variables.

I'm showing an example of how to declare them here...

When you declare something,

you need to know the type of variable to use first.

For example, an integer...

You give it a name, and then a value.

That's just assigning 293,193 to the variable.

I've got an example of all the upper and lower bounds
of each of these types.

Bytes are 1 byte unsigned integers,

I'll run the program so you can see.

Byte is unsigned. So that's 0 to 255.

Short is a two byte signed integer,
-32,000 up to 32,000.

Integer is a four byte signed integer,
from ~-2 billion to ~2 billion.

Long is...

~-9 centillion to ~9 centillion.

So, they're getting a bit big here!

Double is eight byte floating point numbers.

So, for example, 1.7 is a double, or 9.8, and so on.

Doubles range from
~-1.79×10^308 to ~1.79×10^308

Doubles have a huge range!

Decimals are sixteen byte decimal numbers,
and they range from ...

I'm not even going to attempt to break that down...

It can handle both decimals and whole numbers.

Boolean is a true/false value, or 1/0.

And they can be assigned like this...

Boolean, then a name, then a value.

Char is a character, which represents a single unicode character.

You can view all of these on the ASCII sheet,

basically, anything you can type on the keyboard,

but only one character.

For example, a space, or a question mark.

String are made up of a sequence of chars (or characters),

I've just assigned "Hello" to this one,
but they can hold any string of characters.

String accepts absolutely anything on the keyboard as well.

Those are all of the data types,

I'm now going to show you some math you can do with them.

Now, all numeric values can be used in arithmetic calculations.

For example, the decimal value...

the decimal value of 10.2...

can be added to the integer value of 2.

And if we write this out to the console...

and cast the decimal to a decimal,

because the program thinks it's a double,

so we put the little 'm' at the end to make sure
the program knows it's a decimal.

And it will give us...

12.2

Arithmetic can also be used on characters.

The program uses the numeric value of a character in the arithmetic.

For example, if we have the character 'Z', and add 2 to it...

the ASCII value for the 'Z' will be used...

this is called casting.

Casting will take whatever variable type comes out of this
and cast it as another type.

So this will go two places through the ASCII table from 'Z',

which is a backslash.

So that's arithmetic with chars.

Chars can also be added to strings. For example...

These double quotes are for assigning strings,

so a string can also be a single char (character).

If we want to make sure it's a char we're adding to it,

we use single quotes.

It still has the same effect, but the difference is:

a string uses double quotes, and a char uses single quotes.

There are some cool little functions you can do with primitive variables.

(Plus plus) will increment it by 1.

When we output it again, the answer will be 2.

(Minus minus) will decrement it by 1.

This value of "test" can be changed (reassigned) like this...

We can assign it to the variable name (the old value)
plus 10.

We assigned it there, then we output 1.
Increment it by 1 = 2. Decrement it by 1 = 1.

Add 10 = 11.

There are other cool things, but that's the basic stuff.

You can also do the same thing with minus,
and there are some shorthand ways as well.

Plus equals (+=) is [increment and reassign].

That's all the basics when it comes to primitive variables
and arithmetic.

So, this has been the second part of How To: Beginner Programming.

More parts will be released shortly,

again I'll leave a gap between videos to allow you to
ask any questions you might have,

and I'll answer them in the next video.

I only had one question (last video), and that was,

why do I use C# over another language?

And that's because C#, I think, is a nicer language to begin with

than Visual Basic.

Because Visual Basic teaches awful practices,

and the structure of the code can be awkward.

If you go from Visual Basic to another language,

which you probably would,

then you carry over some bad practices.

C++ is incredibly involved when you get into arrays,

and we haven't gotten to arrays yet,

but in C++ you're accessing pointers in memory,
whereas C# handles all of that background stuff for you.

In C++ you have to handle it all yourself.

That's why I picked C#.

Thanks very much for watching!

Again, leave any questions in the comment section below.

See you next time for episode three!