title: Is there a way to automatically generate the data flow diagrams and flowcharts?
body: <p>I am recently working on some long and obscure codes written by some other smart guys. 
  I'm thinking of generating the Data Flow Diagrams and the Flowcharts to facilitate my work. Is there any kinds of software that can do this job automatically?
  P.S. Most of the codes are in C and Fortran.</p>