Numbers and text - TorbScript

A program can calculate: + adds, - subtracts, * multiplies and / divides. When what you print is a calculation, put it in parentheses, so the computer knows it all belongs to print.

Whole numbers stay whole: 7 / 2 is 3, with the rest dropped. For a result with a decimal point, write the numbers with one: 7.0 / 2.0 is 3.5.

const price = 4
const count = 3
print(price * count)
print(7 / 2)
print(7.0 / 2.0)
// prints 12
// prints 3
// prints 3.5

Text#

Text is joined with +, and it has things it can do, which are written after a dot: full.toUpperCase() gives the same text in capital letters.

const first = "Ada"
const last = "Lovelace"
const full = first + " " + last
print full
print full.toUpperCase()
// prints Ada Lovelace
// prints ADA LOVELACE

Every value has a type#

A whole number like 12 is an Int, a number with a decimal point like 3.5 is a Float, and text like "Ada" is a String. That kind of value is called its type.

The type decides what works: text and a number cannot be added with +, because it is unclear what that should mean. To put a number into text, use curly braces: "Age: {age}".

What happens if you add text and a number?

The computer finds it before the program runs:

Does not compile

print "Age: " + 36
// error: Expected `String`, found `Int64`

Int64 is the full name of Int: a whole number that fits in 64 bits.

Exercise#

A ticket costs 12 and you buy 3. Make the program print Total: 36 by calculating the total instead of printing 0.

const pricePerTicket = 12
const tickets = 3
print "Total: 0"

Expected output

Total: 36

Run it on your computer: torb run numbers-and-text.trb

Hint

Give the total a name with const total = ..., then put {total} into the text.

Solution

const pricePerTicket = 12
const tickets = 3
const total = pricePerTicket * tickets
print "Total: {total}"
// prints Total: 36

Recap#

Numbers calculate with + - * /, text joins with +, and every value has a type: Int, Float or String.