The user is supposed to enter either a yes or no in response to a prompt. The script will print OK, continuing if the user enters either a y, Y,'Yes', or 'yes' or it will print OK, halting if the user enters a n, N, 'No', or 'no' or will print Error if the user enters anything else. Code this twice once with if and once with switch:

Lets recode the example above to keep prompting until an an acceptable yes or no is entered:

What loop should we use? what should we intialize?