table construction & unpack()

Part of the Logic & Flow section of Coddy's Lua journey — lesson 6 of 54.

Lua provides a complementary pair of techniques for working with multiple values: table construction and unpack(). These are particularly useful when working with functions that need flexible argument handling.You can capture multiple values into a list-style table using table constructor syntax with curly braces. This collects all the values into a single table structure.

local args = {10, 20, 30}
print(args[1])  -- Output: 10
print(#args)    -- Output: 3

The unpack() function does the opposite—it takes a list-style table and returns all its elements as separate values. This allows you to pass table contents as individual arguments to a function.Important: While newer versions of Lua (5.2+) moved this function to table.unpack(), this environment runs Lua 5.1, so you must use the global unpack() function.

local numbers = {5, 10, 15}
print(unpack(numbers))  -- Output: 5    10    15

These techniques work together seamlessly. You can collect values into a table, manipulate the table, and then unpack it back into individual values.

Challenge

Easy

Write a function forwardArguments that takes three numbers a, b, and c, and returns their sum by using table construction and unpack().

Create a table containing the three arguments using {a, b, c} syntax, then unpack them and pass them to another function that calculates their sum.

Note: Please use the global unpack() function rather than table.unpack() to ensure compatibility with this environment.

Logic:

Use {a, b, c} to create a table containing all three arguments
Create a separate function called sum that takes three parameters and returns their sum
Use unpack() to pass the table values to the sum function
Return the result from the sum function

Parameters:

a (number): First number
b (number): Second number
c (number): Third number

Returns: The sum of all three numbers (number)

Try it yourself

function forwardArguments(a, b, c)
    -- Create a separate function that calculates the sum

    -- Create a table containing all three arguments

    -- Unpack the table and pass values to the sum function
    -- Hint: Use the global 'unpack' function to expand the table arguments

end