Question

Purpose: Create a program that takes two separate files, opens and reads them, assigns their contents to arrays, do some math with those arrays, create a new array with product numbers, print to a new file. Simple enough right?

My input files have comment characters at the beginning. One trouble is, they are ‘#’ which are comment characters for most plotting programs, but not FORTRAN. What is a simple way to tell the computer not to look at these characters? Since I have no previous FORTRAN experience, I am plowing through this with two test files. Here is what I have so far:

PROGRAM gain
  IMPLICIT NONE
  REAL, DIMENSION (1:4, 1:8)     :: X, Y, Z
  OPEN(1, FILE='test.out', &
        STATUS='OLD', ACTION='READ')            ! opens the first file
  READ(1,*), X
  OPEN(2, FILE='test2.out', &
    STATUS='OLD', ACTION='READ')            ! opens the second file
  READ(2,*), Y
  PRINT*, X, Y

  Z = X*Y
!  PRINT*, Z
  OPEN(3, FILE='test3.out', STATUS='NEW', ACTION='WRITE')   !creates a new file
  WRITE(3,*), Z
  CLOSE(1)
  CLOSE(2)
  CLOSE(3)
END PROGRAM

PS. Please do not overwhelm me with a bunch of code monkey gobblety gook. I am a total programming novice. I do not understand all the lingo, that is why I came here instead of searching for help in existing websites. Thanks.

Answer 1

Write a subroutine that puts this logic into one spot for you so you can call it for both files. You’ll need to read each line as a string and add an IF test to check whether a given line starts with a “#” or not. If the line starts with a “#”, just read the next line. If not, convert the string to a value and add it to the array of values you’re returning.