fortran90

This question already has an answer here: Array First Index in Fortran 2 answers Can someone explain what is zero indexed array in Fortran along with example. I'm not getting any content on that on internet. A zero indexed array is an array who's index origin is ZERO . This means that the first element of the array is referenced by index 0 . Fortran arrays defaultly start with index 1 when you declare them INTEGER, DIMENSION(3) :: v Here, the symbol v represents a one-dimensional array of size 3 with elements v(1) , v(2) and v(3) . However, the Fortran standard gives you the possibility to set

How to avoid repeated declaration of a variable that has a constant value in subroutines? For example: program test implicit none integer :: n integer :: time print*, "enter n" ! this will be a constant value for the whole program call Calcul(time) print*, time end program subroutine Calcul(Time) implicit none integer :: time ! i don't want to declare the constant n again and again because some times the subroutines have a lot of variables. time = n*2 end subroutine Sometimes there are a lot of constants that are defined by the user and I will make a lot of subroutines that use those constants

I want to calculate z value as the coordinate in range of x:-50~50 and y:-50~50 like below code. program test implicit none ! --- [local entities] real*8 :: rrr,th,U0,amp,alp,Ndiv real*8 :: pi,alpR,NR,Rmin,Rmax,z integer :: ir, i, j do i=0, 50 do j=0, 50 th=datan2(i,j) pi=datan(1.d0)*4.d0 ! Ndiv= 24.d0 !! Number of circumferential division alp = 90.d0/180.d0*pi !! phase [rad] U0 = 11.4d0 !! average velocity amp = 0.5d0 !! amplitude of velocity Rmin = 10 !! [m] Rmax = 50 !! [m] NR = 6.d0 !! Number of radial division ! rrr=dsqrt(i**2+j**2) ir=int((rrr-Rmin)/(Rmax-Rmin)*NR) alpR=2.d0*pi/dble(Ndiv

I am using a Fortran 90 program that writes a file. The first line of this file is supposed to indicate the number of lines in the remaining file. The file is written by the program when a certain criterion is met and that can't be determined beforehand. Basically, I will know the total number of lines only after the run is over. I want to do it in the following manner: 1) open the file and write the first line with some text say, " Hello " 2) Write rows in the file as desired and keep a counter for number of rows. 3) Once the run is over and just before closing the file, replace the first

I would like to have some clarifications about the way Fortran handles "empty" characters in strings. Let us assume we have this situation: program main implicit none test('AB') end program where function test(name) implicit none character(10) :: name character(3) :: cutname write(*,*) '-'//name//'-' ! Gives output "-AB -" ! Space has then been added at the end cutname(1:3) = name(1:3) write(*,*) '1-'//cutname//'-' ! Gives output "-AB -" ! It seems there is a space then at the end ! of cutname write(*,*) (cutname(1:2) == 'AB') ! Gives output T (true) write(*,*) (cutname(3:3) == ' ') ! Gives