Changes between Initial Version and Version 1 of cypress/Programming/ApproximatePi/FortranExample

Timestamp:

05/14/15 14:41:22 (10 years ago)

Author:

cmaggio

Comment:

migrated content from ccs wiki

cypress/Programming/ApproximatePi/FortranExample

@@ +1 @@
+= Ex12sq.f90 = 
+{{{#!fortran
+!
+!  Fortran sample
+!  ex12sq.f90
+!  Approximate PI-3.14159265....
+!  with Leibniz Formula
+ 
+program approximate_pi
+implicit none
+  integer :: i,n
+  double precision :: x
+  character(len=32) :: arg
+ 
+  ! Newer version of Fortran can get commadline arguments
+  call get_command_argument(1,arg)
+  if (len_trim(arg) == 0) then
+     call get_command_argument(0,arg)
+     print *,arg," [number of terms]"
+     call exit(-1)
+  end if
+ 
+  ! convert string to integer
+  read(arg,*) n
+  print *,"Start n=",n
+ 
+  x=0.d0
+ 
+  ! sum
+  do i = 0, n, 2
+     x = x + 1.d0 / (2.d0 * dble(i) + 1.d0);
+     x = x - 1.d0 / (2.d0 * dble(i) + 3.d0);
+  end do
+ 
+  print *,"n=",n,"Pi=",4.d0 * x
+ 
+end program approximate_pi
+}}}