reading data from txt file in fortran

Question

I am writing a FORTRAN program that reads data from a text file and writing it to the console. the data file looks something like this

1234567890123456 12345         


        

Answer 1

I had the hardest time ever trying to use read, but finally... If you want to read a matrix stored in a .txt file use this:

program FILEREADER

   real, dimension(:,:), allocatable :: x
   integer :: n,m

   open (unit=99, file='array.txt', status='old', action='read')
   read(99, *), n
   read(99, *), m
   allocate(x(n,m))

   do I=1,n,1
      read(99,*) x(I,:)
      write(*,*) x(I,:)
   enddo

end

And the "array.txt" file must be like this for instance (And placed in the same folder of the main):

4
3
0.0 1.0 2.0
3.0 4.0 5.0
6.0 7.0 8.0
9.0 10.0 11.0

Hope it works for everyone out there