using keyword and the namespace keyword... can they be used interchangeably ? (don't remember if I once saw a namespace along with a library name... is that even allowed?) .namespace {...}like we have the curly braces but sometimes we don't. My IDE always do the heavy lifting but I wanted to understand what the syntax is :c.using when we need to use certain libraries? While the keyword namespace is used to related to certain folders/cs files? I'm a bit confused here :c... what about the namespace {...} syntax please