Postcode Validator

This is a postcode validator for the United Kingdom in progress.

It works simply via a while loop and some validation.

Validation Criteria

Available Postcode Formats:

AN NAA
ANN NAA
AAN NAA
AANN NAA
ANA NAA
AANA NAA

Where A is an alpha character, and N is a numeric character.

• The letters Q, V, and V can't be used in the first position
• The letters I, J and Z can't be used in the second position
• The only letters which can be present in the third position are A, B, C, D, E, F, G, H, J, K, S, T, U, and W.
• The second half of the postcode will consistently follow the format, 'NAA'
• The letters C, I, K, M, O, and V are not used in the second half.