How to redirect user if they enter an incorrect input

In my program, I prompt the user for an input of a string. If they enter an incorrect input, my program displays the message "Error. Please enter one of the options.". However, my program stops there and doesn't ask for the input again. What would I use to redirect the user back to the input? Thank you.

Answer 1

[Mischa Kim]

Bree, without knowing the structure of your program I would suggest using a while -loop.

Put the prompting commmand into the loop and set a flag that causes the loop to be excited once the input is "correct".

 FLAG = false;
 while ~FLAG
    % the input prompt would go here

    if *input is correct* % replace accordingly
       FLAG = true;
    end
 end