Problem: Write a Lex program for checking a valid URL.
Lex is a computer utility that generates some lexical analyzers. Lex reads a stream of characters as input specifying the lexical analyzer and give source code as the output implementing the lexer in the C programming language.
Prerequisite: Flex (Fast Lexical Analyzer Generator)
Input: geeksforgeeks Output: INVALID URL Input: https://www.geeksforgeeks.org Output: VALID URL
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