Libraries Question

[Strudul]

How do I know which libraries are needed in my program?

At first I included five to be on the safe side, but I took some out and am now down to two, windows.h and iomanip.h (and using namespace std).

Everything seems to work perfectly and there are no errors.

OS: Windows 7 and XP
Compiler: Dev-CPP

[ResidentBiscuit]

Uh well that depends on what your project is doing. If it runs fine, I'd say you have everything you need

[Moschops]

Those are headers, not libraries. If your code compiles, you've included all the headers you need.

[ne555]

RTFM, it will tell you in which header is the function declared.
iomanip.h doesn't exist.

Edit: You should include all those headers.
If not, your code may not compile with another compiler (or version)