C99 or C11?

Serious topic. No mention of C89 as it is objectively inferior to C99.

I remember when I first tried to compile a C program with Microsoft's C compiler (I was an ENTERPRISE SEPPLES ``developer'') and it wouldn't, and I didn't understand why. The reason why was that Microsoft's C compiler only compiles C89, and C89 required that every variable be declared at the start of each block.