refactoring

Anthropic-style screens open with deceptively simple builds like this, then extend them three times. The grade isn't the counting; it's whether your first version survives the extensions without a rewrite.

The function reads a file, parses it, computes a metric, and prints, all tangled together. The move interviewers want is not prettier code, it's pulling pure logic out from side effects so each piece can be tested in isolation.