Flashback... When trying C for the first time, I ported a ~300 line Pascal program. I had read C syntax for some time, and the program was rather simple so I felt confident in the job.

After transcribing the ~300 lines I tried to compile for the first time: 3728 errors and warnings...

I read through the code and everything looked correct, so I gave up.

Picked it up again some weeks later. Turned out that I had, by force of habit, erroneously added a semicolon at the end of macro definition on line 3. Fixing that it compiled flawlessly.

At the time I was also unaware that I was actually using a C++ compiler, djgpp, which I'm sure did the error count no favors.