include 'mpif.h'

      integer ierr

      character*100 filename
      character*10  digit_string
      integer p
      integer my_rank
      integer size
  

      call MPI_Init(ierr)

C     Get my_rank
      call MPI_Comm_rank(MPI_COMM_WORLD, my_rank, ierr)
C     Get the number of Processes
      call MPI_Comm_size(MPI_COMM_WORLD, p, ierr)
      
      call seed_random_numbers( my_rank)

C     Convert my_rank to a charactoer string
      call to_string(my_rank, digit_string, size)
C     Concat "file" and the string for my_rank
      filename='file.' // digit_string(1:size)
      

C     Open a file for each process for I/O
      OPEN(unit=7,file=filename,status='unknown')
      WRITE(7,*)'Hello World from ',my_rank
      call MONTE_CARLO()
      CLOSE(7)
      call MPI_Finalize(ierr)
      end
      


cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
c
c   Converts the integer stored in number into an ascii 
c   string.  The string is returned in string.  The number of 
c   digits is returned in size.
        subroutine to_string(number, string, size)
        integer number
        character *(*) string
        integer size

        character*100 temp
        integer local
        integer last_digit
        integer i

        local = number
        i = 0

c   strip digits off starting with least significant
c   do-while loop
 100        last_digit = mod(local,10)
            local = local/10
            i = i + 1
            temp(i:i) = char(last_digit + ichar('0'))
        if (local.ne.0) go to 100
        
        size = i

c   reverse digits
        do 200 i = 1, size
            string(size-i+1:size-i+1) = temp(i:i)
 200    continue
c
        return
        end
c   to_string
c