x++ / Tutorials / 3. Branches
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Lesson
In the previous lesson, you learned how to get a user input and modify them to get a certain result. In this lesson, you will be learning how to create a branch using the if operator.
The if operator takes 3 arguments, the expression, the true branch, and the else branch. An expression is an equation that evaluates the two sides. An expression is made up of 3 parts, the source, the comparator, and the target:
<source> <comparator> <target>
For example, the equal to comparator looks like this:
var myInteger 5
myInteger == 5
If the expression is true, the if operator will then trigger the true branch, else the false branch. Both branches must be a string and their contents must be a valid statement.
Because the branches are strings, if you want to use another (double-quoted) string within the branch, you have to escape it. This is done by appending a backslash (\) right before the double-quote.
Now let's put it together:
var myAge 20
if (myAge == 20) { prt "I am 20 years old" } { prt "I am not 20 years old" }
When you run the code, you should see it outputs "I am 20 years old". Try changing the value of myAge and see what happens.
The else branch is optional. If you only want to check if the expression is true, you can just use one branch instead:
var myInteger 5
if (myInteger == 5) { prt "My integer is 5" }
With that knowledge, you can now output a special text if the user name matches yours:
:: main.xpp
read "What is your name? " ?name
read "What is your age? " ?age
:: Keep a copy of their original string
var ogName name
:: Calculate birth year by using the current year
int age :: Ensure it's an integer
sub 2024 age ?birthYear
:: Convert the name to lowercase (so we can check it)
if ((lwr name) == "bob") { prt "Welcome, Bob!" }
:: Show them their info
prt "Your name is $(ogName) and you were born in $(birthYear)."
There are many more comparators, such as the greater than (>) or not equal (!=). They work the same way as the equal to comparator.
Now's your turn. Check if the user's age is equal to or above 16 and output "You can also drive a car" after you output their name and their birth year if it is true.
Did you get something like this?
:: main.xpp
read "What is your name? " ?name
read "What is your age? " ?age
:: Keep a copy of their original string
var ogName name
:: Calculate birth year by using the current year
int age :: Ensure it's an integer
sub 2024 age ?birthYear
:: Convert the name to lowercase (so we can check it)
if ((lwr name) == "bob") { prt "Welcome, Bob!" }
:: Show them their info
prt "Your name is $(ogName) and you were born in $(birthYear)."
if (age >= 16) { prt "You can also drive a car." }
In the next lesson, you will be learning how to make a calculator using x++.
Last Updated: March 9th, 2024 by iiPython