@EnjuAihara "a" is a completely legitimate variable names. Usually when I do multiple nested for loops I use the first letter[s] for the iterator variable. Also if it's short lived and generic it works.
@EnjuAihara No, it depends. It actually makes sense you'd want something short if you call it often, and if it's scoped to that function and it's purpose is clear, than that makes a lot of sense.
A real world example would be something like lua. In the C API almost everyone always calls the lua_State* just "L" and it's scoped to entire functions. (pic of awesomewm spawn.c)