MOAR DATA TYPES

I apologise for constantly retracing the same ground but digging a bit deeper, but hopefully later on you will thank me as you will be super grounded in what im waffling about.

So if we rewind we have so far spoken about int, float, string variable types. These are super common and you will be using these a lot, but there are also other data types which are more niche, so lets cover all common types.

Not all languages will support all these types, but most do. For example C#, Java, C/C++ and many others all have the notion of these variable types.

Common Types

All the code examples shown below will be in C#, but the syntax is pretty similar as we showed before.

Boolean

This data type has 2 possible values, true or false. So if I were to ask you "Do you like peas?" you would ask your brain and it would tell you "yes" or "no", same sort of thing here.

bool doesPersonLikePeas = true;

Byte

This is where we start getting into the deep stuff, a byte is a numeric value which can only store values between 0-255.

Day to day you wont really use a byte much by itself, as it tends to be used like a string where a collection of bytes make up a data stream of sorts.

byte aByte = 128;

Bytes actually are very important from a technical perspective as you can actually look at almost all other types as many bytes glued together, and we will talk about that more later.

Int

We have already discussed integers at a high level but there are actually a few different types of integers which are available depending on how big your values need to be.

There is also the notion of signed and unsigned integers, which we wont go into here but they basically allow you to store higher values removing the ability to hold negative numbers.

Int16 / Short

This is the 2nd smallest int as a byte is technically a type of integer. It is known as int16 or short (they both mean same thing) and it can store a value between -32,768 to 32,767.

short aSmallValue = 128;

Int32 / Int

This is the most common int, and if you were to just use int this is the type of integer you would be provided. It can store a value between -2,147,483,648 to 2,147,483,647.

int aDefaultIntegerValue = 128;

Int64 / Long

This is the biggest common integer and can store numbers between -2,147,483,648 to 2,147,483,647.

long aSuperBigIntegerValue = 128;

You may be wondering why we have this many int types, and we are about to see there are lots of float types too, but we will address the WHY shortly

Float

Like int we have already discussed float but there are a few different flavours.

Float / Single

A float can also be known as a single and is the default float provided to you, it can store 6-9 digits accurately. So unlike an integer type which stores a value between a min and max a float is more geared for accuracy so you could have 6-9 (depending on language) digits and have the decimal place anywhere, be it 1.23456789 or 123456.789. If you try to store more digits it just truncates it.

float someValueThatSupportsDecimalPlaces = 128;

Double

This name makes more sense if you think of a float as a single, but this is the same sort of thing, just allows more accuracy giving 15-17 digits of precision (again depending on language).

double someEvenLargerValueSupportingDecimals = 128;

I am purposely not showing decimal place values for a reason which we will get onto later, as sometimes you need to explicitly infer the way a number should be processed, and thats something we shouldn't worry about right now.

Char

A char is just a single character/letter, however under the hood really its just an integer of sorts, and depending on language can store the same values as a byte or short.

If I asked you to tell me the 3rd letter of the alphabet, you could hopefully tell me its C, and the same sort of notion applies here with char types, they use numbers as letter indexes.

char someLetter = 'H';

Notice that we are using single quote/apostraphes here rather than double quotes? That is because we use single quotes for a single character or double quotes for a string

You don't really need to care about this for now but its interesting to point out that most of these types realistically can be seen as numeric when we look closer.

String

As mentioned before a string is just a sequence of characters which are all contextually related. So if we were to dig a little deeper at a string with a value HELLO it's actually just 5 char values all stringed together.

string someText = "Hello";

Strings can contain as many or little characters as you want, so where other types are often fixed in terms of their value sizes, strings can expand as needed so they have no fixed value range.

Why do we need so many types?

This is an excellent question, why have a byte that can only store 0-255 vs a long that can store quintillions? surely it would be better to just use long everywhere and never have to worry about if we can fit the value.

The reason is because each variable takes up varying amounts of memory, which we will dive into a bit more in the next chapter.