I define some function in my ANSI C program (simple program). How can I represent a function in a flowchart?
On a flowchart, a function can be anything: a state, an action that occurs while transitioning betwwen states, etc. It all depends on how you have your flowchart organized. I would recommend building your flowchart normally, then go back and add a function name to the description of anything that is implemented by a function.