While in Lua

The while loop in Lua is used to repeat a set of statements while a certain condition is true. The basic syntax of a while loop in Lua is:

while condition do
  -- statements to be executed
end

The condition is evaluated at the beginning of each iteration. If the condition is true, the statements within the loop are executed. After the execution of all the statements, the condition is evaluated again, and this process continues until the condition becomes false.

Here is an example of using the while loop in Lua to print the numbers from 1 to 10:

local i = 1     -- initialization
while i <= 10 do  -- condition
  print(i)        -- statements to be executed
  i = i + 1       -- update of the counter variable
end

This will output:

1
2
3
4
5
6
7
8
9
10

In this example, the while loop is executed as long as the value of i is less than or equal to 10. Inside the loop, the value of i is incremented by 1 at the end of each iteration using the expression i = i + 1.

Another example of using the while loop in Lua is to keep prompting the user for input until a valid value is entered:

local valid_input = false     -- initialization
while not valid_input do      -- condition
  print("Enter a number: ")
  local input = io.read()    -- read user input
  if tonumber(input) then    -- check if input is a number
    valid_input = true       -- set flag if input is valid
    print("Input accepted: " .. input)
  else
    print("Invalid input. Please try again.")
  end
end

This will keep prompting the user to enter a number until a valid number is entered. Once a valid number is entered, the loop will exit and the program will continue.