How to profile?

I've developed a little screenshot application but I've heard that I should profile my code to see where it's using a lot of resources and stuff.

What is a profiler? what does it do? Where can i get it for free? and How do I use it?

From stackoverflow

• What language are you developing in? For C#, check this question.

  http://stackoverflow.com/questions/10644/any-decent-c-profilers-out-there

  Here's one for C++

  http://stackoverflow.com/questions/170036/decent-profiler-for-windows

  In fact, check the profiler tag to see all the questions tagged in connection with profilers.

  http://stackoverflow.com/questions/tagged/profiler

• A profiler is a software tool which intercepts and measures every executed code path in a certain run of an application. They store this information and later report graphically (or tabularly) where does your code spend most of the running time so you can optimize where it really matters.

  About where to get one, it depends on your platform/language combination.

• See:

  what-techniques-can-you-use-to-profile-your-code

  You didn't say what language you use. For C/C++ (and probably others) a free ones are:

  gcov
  gprof