FORTRAN 90
Lecture : Rafel Hekmat Hameed
University of Babylon
Subject : Fortran 90
College of Engineering
Mechanical Engineering Dep.
Year : Second B.Sc
FORMAT Statement
The format statement may be used to read or write data in a form other
than the default format. A format statement is a labeled statement and may be
used by a WRITE or READ statement within the same program unit by
specifying the label number as the second parameter, for example:
READ (*,100) i, j
WRITE (*,100) i, j
WRITE (*,200) x, y
.....
100 FORMAT (2I)
200 FORMAT (2F10.6)
The general form of a FORMAT statement is
label FORMAT (flist)
where flist is a list of edit descriptors which include
I,F,E,ES,EN,D,G,L,A,H,T,TL,TR,X,P,BN,BZ,SP,SS,S,/,:,',(,)
only the following will be covered
I,F,E,ES,EN,A,X,/,:,',(,)
The labeled FORMAT statement may be replaced by specifying the format
descriptor list as a character string directly in the WRITE or READ statement,
as follows:
READ (*,'(2I)') I, J
WRITE (*,'(2F12.6)') X, Y
ϭ
 INTEGER
The edit descriptor I is used to control the format of integers and can have
the form Iw or aIw For example:
INTEGER :: itest=1234567 !number to write
...
WRITE(*,*) itest
! 1234567
WRITE(*,’(I6)’) itest
!******
WRITE(*,’(I10)’) itest ! 1234567
WRITE(*,10) itest
10 format (I10)
1
2
3
4
5
6
7
4
5
6
7
1
2
3
WRITE(*,’(2I7)’) itest
1
2
3
4
5
6
7
WRITE(*,10) itest
10 format ("itest=", I10)
Integer ::A=44 , b=-50
WRITE(*,100) a,b
100 format (2I3)
4
4
-
5
0
 Real – Fixed Point Form
The Fw.d descriptor is for REAL output.
F is for REAL
w is the width of field, which indicates that a real number should be printed
with w positions.
d indicates the number of digits after the decimal point. This is shown in the
figure below:
REAL :: itest=123.4567
WRITE(*,’(F10.4)’) itest
1
Ϯ
2
3
.
4
5
6
7
Consider the following example:
REAL :: a = 12.34, b = -0.945, c = 100.0
WRITE(*,"(3F6.2)") a, b, c
 Real - Exponential Form
The edit descriptor E is used to control the format of real numbers where
a floating decimal point notation is required. It has the form Ew.d
The Ew.d descriptor generates real numbers in the following form:
Of these w positions, the last three are for the exponent, including its sign,
the middle d positions are for the number in normalized form.
The Ew.dEe descriptor generates real numbers in the following form:
Examples
 Character
The A edit descriptor is used to control the format of characters and
strings. It has the form A or Aw. The A descriptor will writes as many
characters as required while Aw writes a string of width w. If w is bigger than
ϯ
the character string leading spaces are added before the string’s characters. For
example:
CHARACTER(LEN=8) :: long=’Bookshop’
CHARACTER(LEN=1) :: short=’B’
...
WRITE(*,*) long
! Bookshop
WRITE(*,’(A)’) long
!Bookshop
WRITE(*,’(A8)’) long
b
o
o
k
s
h
o
p
b
o
o
k
s
b
o
o
k
s
h
b
b
o
o
WRITE(*,’(A5)’) long
WRITE(*,’(A10)’) long
o
p
WRITE(*,’(A)’) short
b
WRITE(*,’(2A3) short, long
 The L Descriptor
The Lw descriptor is for LOGICAL output. While Fortran uses .TRUE.
and .FALSE. to indicate logical values true and false, respectively, the output
only show T and F. The general form of this descriptor is as follows:
rLw
The meaning of r and w are:
ϰ
 L is for LOGICAL
 w is the width of field,
field, which indicates that a logical value should be
printed with w positions.
 The output of a LOGICAL value is either T for .TRUE. or F for
.FALSE.
 r is the repetition indicator,
indicator, which gives the number of times the edit
descriptor should be repeated
Examples
Let us look at the following example. There are two LOGICAL variables
a and b with values .TRUE. and .FALSE.,, respectively. In the following table,
the WRITE statements are shown in the left and their corresponding output are
shown in the right.
ϱ