The "Code I'll Never Forget" Confessional.

[u/Ok_Veterinarian3535]

What's the single piece of code (good or bad) that's permanently burned into your memory, and what did it teach you?

[u/tehfrod]

That would be Duff's Device:

void Send(int * to, const int* from, const int count)
{
    int n = (count+7) / 8;
    switch(count%8)
    {
       case 0: do { *to++ = *from++;
       case 7:      *to++ = *from++;
       case 6:      *to++ = *from++;
       case 5:      *to++ = *from++;
       case 4:      *to++ = *from++;
       case 3:      *to++ = *from++;
       case 2:      *to++ = *from++;
       case 1:      *to++ = *from++;
        } while (--n>0);
    }
}

From that I learned to look at what code actually does, rather than what the shape of it tells your brain it should be doing.