FORTRAN

a very simple template:

      program example

      real*8 variable
      
c     this line is commented out.
      variable=3.4
      write(*,*)variable   ! After the exclamation mark is commented out.
      
      stop
      end

Note: spacing is important in Fortran; capitalization (case-sensitivity) is not.

to compile a simple fortran routine: g77 example.F

to define a function:

 real function acosd(x)
        implicit none
        real x
        real raddeg
        parameter (raddeg = 180./3.14159)

        acosd = raddeg * acos(x)
        return
        end

to define a subroutine:

 subroutine function(x)
       ...
       end

to call a function:
call func(a,b) for void functions
t=smear(x) for functions that return a value

comparatives: 3.gt.1 1.lt.3

to raise to an exponent: x=3**1.5

if statements:
if (x.gt.y) then
write(*,*)'yay!'
endif

defining varbs:
integer s1,array(10)
real x,t/3.14/ (The "/3.14/" sets the value of the varb)
logical var/.false./
character*256 ericschar (Characters have size = 2^n.)
character*8 lilchar
complex x
double precision y
real rad (Before defining a paremter, declare its type.)
parameter (rad=2) (If you want to set the variable value in the initial declaration.)

to open a file:

Here we define a character called arg1. Then we fill arg1 with the first argument of the command line. Then we open a file that's name we specified in the first command line argument. We could replace this with open(13,file='filename') Then you have to close the file you opened. Careful...we used the ID #13 here, but some ID #'s are illegal because they are default ID's for FORTRAN. This is beacuse FORTRAN is required by law to suck really hard.

Another way to open a file in Super-K code:
first:
setenv RFLIST rflist.$$.`hostname`
echo '10{{"'$filedir$file'",LOCAL,,RED,,,"recl=5670 status=old"}}' >! $RFLIST
then in source code:
DATA LUNI1 /10/
CALL SKOPENF(LUNI1, 0, 'Z', IERR)
CALL SKCLOSEF(LUNI1)

A note about logical unit numbers (lun): In the example above we wrote to lun=10 when we said "write(10,*)varb". On some compilers you can not have lun's greater than 99. Also, some lun's are reserved and you can not use them.

to book a paw histogram: call hbook1(10,'Zenith Angle',51,-1.0,1.0,0.0)
(ID#,title,number of bins,lower limit, upper limit, always 0.0)
to fill a paw hbook file: call hf1(50,QISMSK,1.0)
where 50 is the logical unit number, QISMSK is some varb, and 1.0 is always there for some reason.

To continue a line that is getting too long:
call set_rflist(10,file_name,'LOCAL',' ','RED',' ',' ',
& tab 'recl=5670',' ',' ')
or like this:
if(ichar(list(i)(j:j)).lt.ichar('0') .or.
> ichar(list(i)(j:j)).gt.ichar('9')) goto 100
or like this:

            if ((abs(ipnu(1)).eq.14.or.abs(ipnu(1)).eq.16)
     $           .and.abs(mode).le.30) then

scientific notation: 3e-3 (float) 5.d-1 (double) 4.q3 (quad)

Reading and Writing:
write to screen: write(*,*)'the value of varb is:',varb
write to file lun=10: write(10,*)varb
(If you haven't opened a file with lun=10, then this command will write to a file called "fort.10".)
read from screen: read(*,*)varb
read from file lun=10: read(10,*)varb

one way to get to label 1001 is like this:
goto 1001
but you can also be sent there like so:
call skread(10,*1002,*1001,*170,*10)
(The function skread can send you to label 1001 based on what happens when it reads in lun=10...note the astericks.)

Hex denoted with the z constructor: parameter (LV_TRGAVAIL_FLAG = z'80000000')

To run a shell script within a fortran program:

      character*600 livetime_cmd
      integer iret
      ...
c-----livetime.sh takes two arguments:
c-----the values of the varb, NRUNSK
      livetime_cmd = './livetime.sh NRUNSK NRUNSK'
      iret = system(livetime_cmd)

to provide an area of shared storage between different subroutines (in f77):

program main
    integer :: a, b
    real :: c
    common /d/ a, b, c
  ...
end program main

subroutine jake()
    integer :: a, b
    real :: c
    common /d/ a, b, c
  ...
end subroutine jake

f90 uses something called "modules" for this instead.

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