Assembly Code File Extension

I'm just beginning to learn assembly code, and am still unsure about something; what file extension would assembly code source use?

You can (probably) use whatever you want. Some common ones are `.s`, `.S`, and `.asm`. Check your compiler/assembler documentation to find out if one is preferred for your system/toolchain. GCC and Clang, for example, will assume a file contains assembly code if you use a `.s` extension. If you use something else, you need to pass an appropriate `-x` flag to have the front-end do the right thing.