Learn how to program games with the LÖVE framework
With programming we can do arithmetics.
What is 3 + 4?
Okay well let's test that. We can use
print(3 + 4) --Output: 7
Run your code (meaning press F6 and then close the window to show the output) and your console should say
Cool! Now what is a + b?
Well it could be anything. That's because "a" and "b" don't have a value. Let's change that.
a = 5 b = 3
Let's take another look, what is a + b? What we're really asking is "What is the value of a + the value of b?". In other words, what is 5 + 3? Which is 8.
To prove that a + b = 8, we're going to print it.
a = 5 b = 3 print(a + b) --Output: 8
Run your code again.
b are what we call variables. A variable is a word in which you can store a value. The number 3 is always 3, and 7 is always 7, but a variable can be anything you want it to be. Hence the name variable.
The word in which you store a value can be almost anything.
sheep = 3 test = 20 PANTS = 1040 asdfghjkl = 42
Variables are case-sensitive. That means that when you have the same word, but with different casing, it's not treated as the same. For example
sheep = 3 SHEEP = 10 sHeEp = 200
are three different variables, with each their own value.
You can do more than just summing up numbers.
a = 20 - 10 --Substraction b = 20 * 10 --Multiplication c = 20 / 10 --Division d = 20 ^ 10 --Exponentiation
For numbers with decimals we use a dot.
a = 10.4 b = 2.63 c = 0.1 pi = 3.141592
Take a look at the following code:
X = 5 Y = 3 Z = X + Y
First we say
X = 5. When we give a variable a value, we call that an assignment. We assign 5 to
X, and 3 to
Y. Next we assign
X + Y to
Z. So now
Z equals 8. Remember that you can always check the value of a variable with
Z = X + Y, it would not affect
Z. It would still be 8.
X = 5 Y = 3 Z = X + Y X = 2 Y = 40 print(Z) --Output: 8
This is because to the computer
Z is not
X + Y, it's simply 8.
A variable can also store text.
text = "Hello World!"
This is what we call a string. Because it's a string of characters.
We can connect strings by using two dots (..)
name = "Daniel" age = "22" text = "Hello, my name is " .. name .. ", and I'm " .. age .. " years old." print(text) --Output: "Hello, my name is Daniel, and I'm 22 years old."
There are a few rules when naming a variable. First of all, your variable may have a number in it, but not at the start.
test8 --Good te8st --Good 8test --Bad, error!
Your variable name also can't include any special characters like @#$%^&*.
And finally, your variable name can't be a keyword. A keyword is a word that the programming language uses. Here's a list of keywords:
and break do else elseif end false for function if in local nil not or repeat return then true until while
Variables can be used to keep track of things. For example, we can have the variable
coins, and every time we pick up a coin we can do
coins = coins + 1.
Variables are words in which we can store a value like a number or text. You can name them whatever you want, with a few exceptions. Variables are case-sensitive.
Do you need help or do you see a mistake?
Leave a comment or edit this chapter.