What are the key differences between TCP and UDP, and in what scenarios would you choose one over the other?

TCP (Transmission Control Protocol) provides reliable, connection-oriented communication with error checking, flow control, and congestion control. UDP (User Datagram Protocol), on the other hand, is connectionless and provides unreliable, datagram-oriented communication without built-in mechanisms for error recovery or flow control. TCP is typically used for applications requiring reliable data delivery, such as web browsing, email, and file transfer, while UDP is preferred for applications where low latency and reduced overhead are more important, such as real-time multimedia streaming, online gaming, and VoIP.