title: How to call and use a subroutine inside another subroutine in fortran?
body: <p>I am doing a program in which the main contains many subroutines and functions. For constructing one of these subroutines of the main (let's say subroutine A) I need to make use of another subroutine (let's say B). My question is, how can I make subroutine A call and use subroutine B? I am a beginner and I have searched a lot but found nothing that I understand clearly...</p>
  
  <p>Any help would be appreciated, thanks in advance!</p>