String or Char Arrays Length Definition

Using Arduino Programming Questions
30
  • INPUT: "1" ; OUTPUT: "1"
  • INPUT: "12345" ; OUTPUT: "12345"
  • INPUT: "12345678" ; OUTPUT: "12345678"
  • INPUT: "123456789" ; OUTPUT: "Invalid Input, please enter 3 to 8 characters"
  • INPUT: "12345678901" ; OUTPUT: Blank line, "Invalid Input, please enter 3 to 8 characters" & line with "1"
  • INPUT: "123456789012" ; OUTPUT: Blank line, "Invalid Input, please enter 3 to 8 characters" & line with "12"
  • INPUT: "012345678901234567890123" ; OUTPUT: "Invalid Input, please enter 3 to 8 characters" twice& line with "0123"

I would love to have just the ERROR ONCE. Any ideas, please!!!!