Driven By Code

The characters escaped on strings?!

Tue, 26 Feb 2013 21:19:00 -0600

You'll notice that C# is a bit funny when it comes to how it treats strings, at least as compared to some other languages. For example, let's say you were to write...

string TheCow = "Goes \moo!";

Visual Studio will start barking at you about an “Unrecognized Escape Sequence”. This is because interprets the backslash as the beginning of a special character sequence. Now, let's say you were to write something like...

string TheCow = "Goes \\moo!";

All would be well in the world of compiling and Visual Studio would be happy. Your string would be displayed as “Goes \moo!” though. Welcome to the world of character literals and escape characters... and while there are a great many of these little guys in the world of C# let's just take a look at a few of them.

\” will produce a double quote, or “.
\n will produce a new line, or line break... depending on your favored terminology.
\t will produce a horizontal tab, or, a tab.
\\ will produce, like shown above a single back slash.

It is also noteworthy that the single backslash can be used to create all sorts of symbols, such as the ones found in the character map. For example if you happen to know that hex code for an upside down “a” you could type \x250 to produce just that symbol. Not entirely sure why one would need an upside down “a”... but hey, whatever floats your boat.

Escape characters can cause a fair amount of confusion when the proper attention isn't being given, for example, let's say we want to assign a path to a string for later use...

//Here, we make Visual Studio very, very angry.

string PathToBacon = "c:\Bacon\";

//Here, we don't.

string PathToBacon = "c:\\Bacon\\";

Alternatively we can also turn escaping completely off with the use of the “@” symbol... like so.

//@ Bacon for all!

string PathToBacon = @"c:\Bacon\";

Are you thoroughly confused yet? Well don't be, it only gets more “interesting” here on out.

Variables and DataTypes.

Tue, 26 Feb 2013 17:48:00 -0600

Note - Code snips from now on will be color coded in the same manner Visual Studio 2012 colors text.

In a previous article you saw me declare a string by the name of “sRing” and assigned it a value of “My precious!”... if you have no idea what I'm talking about it means you haven't been paying attention and will need to stay after class... anywho. In the case I just mentioned, “sRing” would be the variable, and “string” would be the data type. Here are two more examples of what we like to call “local variables”:

//This is a variable of type "int" or interger by the name of "TheAnswer".

int TheAnswer;

//This is a variable of type "bool" or boolean by the name of "CorrectAnswer".

bool CorrectAnswer;

Notice the above examples are slightly different than before, I haven't assigned them a value just yet. While this is actually a fairly standard practice , it's important to not that you cannot use a variable until it has been assigned a value... if you try, well, let's just leave it at things go all sideways and break. With that being said, let's assign these bad boys some values shall we?

//This is a variable of type "int" or interger by the name of "TheAnswer".

int TheAnswer = 42;

//This is a variable of type "bool" or boolean by the name of "CorrectAnswer".

bool CorrectAnswer = true;

Ah, much better. As you can see we have assigned “TheAnswer” a value of 42... as when in doubt the answer is always 42, and our “CorrectAnswer” has been assigned a value of “true”. Quick comment on “CorrectAnswer”, a “bool” or boolean is a variable that can only be assigned a true of false value, remember, “Is Bacon Awesome”? Bacon is always awesome.

While there are subtle differences in how variables are declared across the various .Net languages, the DataTypes themselves are pretty much universal. We can also declare variables by using their entire type class from the .Net Class Libraries, such as....

System.Int32 TheAnswer = 42;

This is also known as using a “fully qualified type name”. You generally will rarely need to do this as “using” statements allow you to call your DataTypes directly, but in some cases when working with third party classes the need will arise, but we will focus more on types and name spaces later. Below is a table of some of the more common DataTypes we will be working with in the articles to follow.

Data Type	Range
byte	0 .. 255
sbyte	-128 .. 127
short	-32,768 .. 32,767
ushort	0 .. 65,535
int	-2,147,483,648 .. 2,147,483,647
uint	0 .. 4,294,967,295
long	-9,223,372,036,854,775,808 .. 9,223,372,036,854,775,807
ulong	0 .. 18,446,744,073,709,551,615
float	-3.402823e38 .. 3.402823e38
double	-1.79769313486232e308 .. 1.79769313486232e308
decimal	-79228162514264337593543950335 .. 79228162514264337593543950335
char	A Unicode character.
string	A string of Unicode characters.
bool	True or False.
object	An object.

A quick word on Code Blocks

Wed, 20 Feb 2013 18:43:00 -0600

In the last article I made a quick comment about not needing to terminate “code blocks”, and while the concept isn't difficult to follow I feel it's important to bring it up now because we are going to be using the crap out of code blocks pretty soon, so let's explore what code blocks are, shall we?

Much like good ole C or Java, C# uses “curly brackets” pretty much everywhere. Yes, I know... stupid term, “curly brackets”, get used to the term because you're going to be using it a lot unless you're like me and refer to them as “drunk parentheses”... which doesn't really go over too well in civil conversation. Anyways, { } or curly brackets are an important as they are a means of group “blocks” of code together for a whole bunch of purposes. What purposes you ask?! Well! How about code that is executed when a certain condition is met, loops, or functions?! ( If you're lost, don't worry we will go over all that a bit later as well. ) These curly little dudes group our code into whats called “block structures”, and a quick example of that is:

if(BaconIsAwesome)

{

//Some slick code goes here, because bacon is ALWAYS awesome.

}

Above is an example of a conditional block. Basically if you read it to yourself out loud is will translate itself to: “If Bacon is Awesome, let's execute some cool stuff”. Considering bacon is always awesome, the code always runs... and there's our curly braces keeping all that code together. We will explore this deeper in upcoming articles but as I said, it's important to lay the ground work for this now so that when I throw it at you later you won't be too confused.