Runtime vs. Compile time

Question

What is the difference between run-time and compile-time?

Answer 1

As an add-on to the other answers, here's how I'd explain it to a layman:

Your source code is like the blueprint of a ship. It defines how the ship should be made.

If you hand off your blueprint to the shipyard, and they find a defect while building the ship, they'll stop building and report it to you immediately, before the ship has ever left the drydock or touched water. This is a compile-time error. The ship was never even actually floating or using its engines. The error was found because it prevented the ship even being made.

When your code compiles, it's like the ship being completed. Built and ready to go. When you execute your code, that's like launching the ship on a voyage. The passengers are boarded, the engines are running and the hull is on the water, so this is runtime. If your ship has a fatal flaw that sinks it on its maiden voyage (or maybe some voyage after for extra headaches) then it suffered a runtime error.