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Beginning Fortran

Fortran (77) Basics

22 October 2009

*Black text on white background provided or eas! printing

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"xa#ple $ode

• %rite a progra# to read in &vevalues o te#perature in Fahrenheitand convert to degrees $elsius O'elvin O' both

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 our +!pical ,rogra#

c234567

  PROGRAM MYPROGRAM

  STOP

  END

 

,rogra#Options

-eclaration o .ariables

/1 $O-"

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 our +!pical ,rogra#

c234567

  PROGRAM MYPROGRAM

  STOP

  END

 

,rogra#Options

-eclaration o .ariables

/1 $O-"

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,rogra# -eclaration

•  ou declare what kind o Fortran &le!ou are writing on the &rst line

•3!ntax4 5+,"6 5/"6

c234567

  PROGRAM CONVERTF

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,rogra# -eclaration

•  ou declare what kind o Fortran &le!ou are writing on the &rst line

•3!ntax4 5+,"6 5/"6

c234567

  PROGRAM CONVERTFSpecifies the file as a program Program name – something short but descriptive

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 our +!pical ,rogra#

c234567

  PROGRAM CONVERTF

  STOP

  END

 

,rogra#Options

-eclaration o .ariables

/1 $O-"

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Options and .ariables

•  +here are nu#erous options !oucan 8oogle the# i !ou are interested

• 1n general there are two kinds4

 – ou can :include; variables ro# another*h &le b! putting include‘.h’in the options section

 – ou can switch on other options abouthow the code is run (8oogle it)

 – %e are going to use implicit none

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Options and .ariables

• ll variables we are going to use #ustbe accounted or in the declarationsection (no i#plicit variables allowed)

implicit none

• %hat do we need<

 – +e#perature in Fahrenheit $elsius elvin

 – =ogicals (do we want $elsius elvin both values

 – 3!ntax4 5+,"6 5/"6

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Options and .ariables

c234567

  IMPLICIT NONE

  PARAMETER NT = 5

  REAL F(NT)

  REAL K(NT)

  REAL C(NT)

  LOGICAL DOC

  LOGICAL DOK

  INTEGER I

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Options and .ariables

c234567

  IMPLICIT NONE

  PARAMETER NT = 5

  REAL F(NT)

  REAL K(NT)

  REAL C(NT)

  LOGICAL DOC

  LOGICAL DOK

  INTEGER I

Specify a special parameter – an

unchangeable value that can

immediately be used (unlike a

variable, which can change value)

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Options and .ariables

c234567

  IMPLICIT NONE

  PARAMETER NT = 5

  REAL F(NT)

  REAL K(NT)

  REAL C(NT)

  LOGICAL DOC

  LOGICAL DOK

  INTEGER I

 Array of !"A#s for $ahrenheit temps

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Options and .ariables

c234567

  IMPLICIT NONE

  PARAMETER NT = 5

  REAL F(NT)

  REAL K(NT)

  REAL C(NT)

  LOGICAL DOC

  LOGICAL DOK

  INTEGER I

 Array of !"A#s for %elvin temps

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Options and .ariables

c234567

  IMPLICIT NONE

  PARAMETER NT = 5

  REAL F(NT)

  REAL K(NT)

  REAL C(NT)

  LOGICAL DOC

  LOGICAL DOK

  INTEGER I

 Array of !"A#s for &elsius temps

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Options and .ariables

c234567

  IMPLICIT NONE

  PARAMETER NT = 5

  REAL F(NT)

  REAL K(NT)

  REAL C(NT)

  LOGICAL DOC

  LOGICAL DOK

  INTEGER I

#ogical' o we want to convert to &elsius

(!*") or not ($A#S")+

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Options and .ariables

c234567

  IMPLICIT NONE

  PARAMETER NT = 5

  REAL F(NT)

  REAL K(NT)

  REAL C(NT)

  LOGICAL DOC

  LOGICAL DOK

  INTEGER I #ogical' o we want to convert to %elvin(!*") or not ($A#S")+

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Options and .ariables

c234567

  IMPLICIT NONE

  PARAMETER NT = 5

  REAL F(NT)

  REAL K(NT)

  REAL C(NT)

  LOGICAL DOC

  LOGICAL DOK

  INTEGER I

nteger that counts from - to for loopover one.dimensional arrays

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 our +!pical ,rogra#

c234567

  PROGRAM CONVERTF

  IMPLICIT NONE

  PARAMETER NT = 5

  REAL F(NT)

  REAL K(NT)  REAL C(NT)

  LOGICAL DOC

  LOGICAL DOK

  INTEGER I

  STOP

  END

 

/1 $O-"

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/ain $ode

• %e need to do several things4

 – 'ead in > values o te#perature

 – -eter#ine i we need to convert to$elsius elvin or both

 – Output values

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F

$rom *ser 

Fi   Ci

K i

o *ser 

o *ser 

o *ser 

!ead in values of $

into array

/&

/%

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F

$rom *ser 

Fi   Ci

K i

o *ser 

o *ser 

o *ser 

$or each of the five

temperatures (for.loop)'

/&

/%

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F

$rom *ser 

Fi   Ci

K i

o *ser 

o *ser 

o *ser 

&ompute & (we are going to do this no matter

what, because we know that the output has to

either be & or % or both, and we need & in

order to calculate % anyway)0

/&

/%

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F

$rom *ser 

Fi   Ci

K i

o *ser 

o *ser 

o *ser 

/utput $ to user (this

should be done 1ust to

make sure that the input

was read correctly)0

/&

/%

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F

$rom *ser 

Fi   Ci

K i

o *ser 

o *ser 

o *ser 

f /& 2 !*", then

output & as well0

/&

/%

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F

$rom *ser 

Fi   Ci

K i

o *ser 

o *ser 

o *ser 

f /% 2 !*", then

compute % from & and

output to user as well0

/&

/%

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/ain $ode

F

$rom *ser 

c234567

  DO I = 1, NT

  READ(*,*) F(I)

  ENDDO

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/ain $ode

F

$rom *ser 

c234567

  DO I = 1, NT

  READ(*,*) F(I)

  ENDDO

!"A is a $ortran command that is used for input0

Synta3' !"A(4location5,4formatting5)#ocation (6) 2 read in from the terminal

$ormat (6) 2 no particular format

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/ain $ode

F

$rom *ser 

c234567

  DO I = 1, NT

  READ(*,*) F(I)

  ENDDO  WRITE(*,*) ‘Convert to C?’

  READ(*,*) DOC

  WRITE(*,*) ‘Convert to K?’

  READ(*,*) DOK

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/ain $ode

F

$rom *ser 

c234567

  DO I = 1, NT

  READ(*,*) F(I)

  ENDDO  WRITE(*,*) ‘Convert to C?’

  READ(*,*) DOC

  WRITE(*,*) ‘Convert to K?’

  READ(*,*) DOK

7rite to screen with no particular formatting0

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/ain $ode

c234567

  DO I = 1, NT

  C(I) = (5./9.)*(F(I)-32.)

  ENDDO

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/ain $ode

c234567

  DO I = 1, NT

  C(I) = (5./9.)*(F(I)-32.)

  ENDDO

$or each temperature'

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/ain $ode

c234567

  DO I = 1, NT

  C(I) = (5./9.)*(F(I)-32.)

  ENDDO

$or each temperature'

&ompute &elsius temp0

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/ain $ode

c234567

  IF (DOK .EQV. .TRUE.) THEN

  DO I = 1, NT

  K(I) = C(I) + 273.15

  ENDDO

  ENDIF

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/ain $ode

c234567

  IF (DOK .EQV. .TRUE.) THEN

  DO I = 1, NT

  K(I) = C(I) + 273.15

  ENDDO

  ENDIF

#ogical trap' f we want to calculate %elvin'

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/ain $ode

c234567

  IF (DOK .EQV. .TRUE.) THEN

  DO I = 1, NT

  K(I) = C(I) + 273.15

  ENDDO

  ENDIF

#ogical trap' f we want to calculate %elvin'

#oop through temperatures and calculate %elvin temps0(f /% 2 0$A#S"0, this entire loop is avoided)

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/ain $odec234567

  IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .FALSE.)) THEN  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C’

  ENDDO

  ENDIF

c

  IF ((DOC .EQV. .FALSE.) .AND. (DOK .EQV. .TRUE.)) THEN

  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, K(I), ‘K’

  ENDDO

  ENDIF

c

  IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .TRUE.)) THEN

  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C ’, K(I), ‘K’

  ENDDO

  ENDIF

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/ain $odec234567

  IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .FALSE.)) THEN  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C’

  ENDDO

  ENDIF

c

  IF ((DOC .EQV. .FALSE.) .AND. (DOK .EQV. .TRUE.)) THEN

  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, K(I), ‘K’

  ENDDO

  ENDIF

c

  IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .TRUE.)) THEN

  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C ’, K(I), ‘K’

  ENDDO

  ENDIF

c234567

PROGRAM CONVERTF

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  PROGRAM CONVERTF

  IMPLICIT NONE

  PARAMETER NT = 5

  REAL F(NT)

  REAL K(NT)

  REAL C(NT)

  LOGICAL DOC

  LOGICAL DOK

  INTEGER I

  DO I = 1, NT  READ(*,*) F(I)

  ENDDO

  WRITE(*,*) ‘Convert to C?’

  READ(*,*) DOC

  WRITE(*,*) ‘Convert to K?’

  READ(*,*) DOK

  DO I = 1, NT

  C(I) = (5./9.)*(F(I)-32.)

  ENDDO

  IF (DOK .EQV. .TRUE.) THEN

  DO I = 1, NT

  K(I) = C(I) + 273.15

  ENDDO

  ENDIF

  IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .FALSE.)) THEN

  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C’

  ENDDO

  ENDIF

c

  IF ((DOC .EQV. .FALSE.) .AND. (DOK .EQV. .TRUE.)) THEN  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, K(I), ‘K’

  ENDDO

  ENDIF

c

  IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .TRUE.)) THEN

  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C ’, K(I), ‘K’

  ENDDO

  ENDIF

  STOP  END

P St tc234567

PROGRAM CONVERTF

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Program Start

Options/Variable Declaration

Main Code

Program End

  PROGRAM CONVERTF

  IMPLICIT NONE

  PARAMETER NT = 5

  REAL F(NT)

  REAL K(NT)

  REAL C(NT)

  LOGICAL DOC

  LOGICAL DOK

  INTEGER I

  DO I = 1, NT  READ(*,*) F(I)

  ENDDO

  WRITE(*,*) ‘Convert to C?’

  READ(*,*) DOC

  WRITE(*,*) ‘Convert to K?’

  READ(*,*) DOK

  DO I = 1, NT

  C(I) = (5./9.)*(F(I)-32.)

  ENDDO

  IF (DOK .EQV. .TRUE.) THEN

  DO I = 1, NT

  K(I) = C(I) + 273.15

  ENDDO

  ENDIF

  IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .FALSE.)) THEN

  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C’

  ENDDO

  ENDIF

c

  IF ((DOC .EQV. .FALSE.) .AND. (DOK .EQV. .TRUE.)) THEN  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, K(I), ‘K’

  ENDDO

  ENDIF

c

  IF ((DOC .EQV. .TRUE.) .AND. (DOK .EQV. .TRUE.)) THEN

  DO I = 1, NT

  WRITE(*,*) F(I), ‘F = ‘, C(I), ‘C ’, K(I), ‘K’

  ENDDO

  ENDIF

  STOP  END

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$o#pilation

• $o#pilation is peror#ed in theter#inal4

3!ntax45co#piler6 ?o 5exec &lena#e6 5source

&lena#e6 5options6

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$o#pilation

• $o#pilation is peror#ed in theter#inal4

3!ntax45co#piler6 ?o 5exec &lena#e6 5source

&lena#e6 5options6epends on system' f88, g88, pgf88, etc0

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$o#pilation

• $o#pilation is peror#ed in theter#inal4

3!ntax45co#piler6 ?o 5exec &lena#e6 5source

&lena#e6 5options67e wish to create an ob1ect that is an e3ecutable file with the following name

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$o#pilation

• $o#pilation is peror#ed in theter#inal4

3!ntax45co#piler6 ?o 5exec &lena#e6 5source

&lena#e6 5options6*se this 60f file to compile the e3ecutable

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$o#pilation

• $o#pilation is peror#ed in theter#inal4

3!ntax45co#piler6 ?o 5exec &lena#e6 5source

&lena#e6 5options6 Also depends on compiler0 Some fre9uent options'

:e3tend – allows you to go over column 8; in the code:bounds – if you attempt to reference an array inde3 out of bounds, will notify you

:byteswapio – some formats re9uire a byte.swap

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$o#pilation

• $o#pilation is peror#ed in theter#inal4

3!ntax45co#piler6 ?o 5exec &lena#e6 5source

&lena#e6 5options6

pgf77 –o CONVERTF.exe CONVERTF.f