Movement Command Controller

Implement a simple up/down/left/right movement controller from a command string, then adapt it when command characters may mix uppercase and lowercase. Requirements Parse a command string containing movement instructions for up, down, left, and right. Use a switch / dispatch table to update the current position. Follow-up: handle mixed uppercase and lowercase command characters. Notes Full input/output shape was not specified, so clarify the initial position, coordinate convention, invalid-character behavior, and expected return value before coding. A clean implementation normalizes each character once, then dispatches through a small mapping from command to (dx, dy). Preparation Write the simple coordinate-update version, then refactor to a map of command deltas. Add tests for lowercase, uppercase, mixed-case, and invalid characters.