Making decisions - TorbScript

A program often has to choose: take a jacket or not. if asks a question, and runs the lines in its curly braces only when the answer is yes. else holds what runs when the answer is no.

The question compares two values: < is less than, > greater than, <= and >= include the value itself, == is equal and != is not equal. Note the two equals signs: one = gives a name a value, two compare.

const temperature = 8
if temperature < 10 {
  print "Take a jacket."
} else {
  print "No jacket needed."
}
// prints Take a jacket.

More than two ways#

else if asks the next question when the one before was answered no. The computer goes from the top and takes the first way whose answer is yes.

The answer to a question is a value too: true or false. Its type is Bool, and a name can hold it like any other value: const isCold = temperature < 10.

const hour = 14
if hour < 12 {
  print "Good morning"
} else if hour < 18 {
  print "Good afternoon"
} else {
  print "Good evening"
}
// prints Good afternoon

Exercise#

Make the program print Adult when age is 18 or more, and Child otherwise. With the age 20, it prints Adult.

const age = 20
print "Child"

Expected output

Adult

Run it on your computer: torb run making-decisions.trb

Hint

Ask if age >= 18, print Adult in its braces, and move print "Child" into the braces of an else.

Solution

const age = 20
if age >= 18 {
  print "Adult"
} else {
  print "Child"
}
// prints Adult

Recap#

if runs its lines when the answer to its question is true, else when it is false, and == compares while = gives a value.