What is FORTRAN?
Fortran is an acronym that is derived from Formula Translation. It is one of the early high level programming languages that were used in the 1960s when the computer revolution begun. BASIC is based on Fortran.
Fortran Interview Questions and Answer: Fortran is a generalpurpose, compiled imperative programming language that is especially suited to numeric computation and scientific computing. FORTRAN is generally the preferred spelling for discussions of versions of the language prior to the current one (‘90”). Fortran is the spelling chosen by X3J3 and WG5. Fortran Interview Questions and Answer: In this document a feeble effort has been made to capitalize accordingly (e.g. vast existing software … FORTRAN vs. generic Fortran to mean all versions of the standard, and specifically the modern dialect, ISO 1539:1991).
State a few advantages of using Fortran
 It supports numerical analysis and scientific computation.
 It is an Object Oriented Programing language
 It is readable and easy to understand
Explain what arrays are in Fortran
A collection of data types or variables. In Fortran programmers can include up to 7 dimensional arrays.
Explain why Fortran is faster than C
When mathematical functions are being evaluated, the former handles memory references very well. C uses pointers that can be challenging to optimize while performing mathematical tasks.
What is a subroutine in Fortran?
A subroutine can modify the arguments of a program although it does not return a value.
What is a module in Fortran?
Functions and subroutines that are stored together so that they can be used in various parts of the entire program. In other words a large program is spliced into modules for simplicity.
Explain using examples how variables are declared in Fortran
The syntax for declaring variables is typespecifier :: list. The type specifier can be INTEGER, REAL, COMPLEX, LOGICAL, AND CHARACTER.
What are reserved keywords?
They are words that cannot be used as identifiers. Fortran does not have reserved words although it has identifiers like END, PROGRAM, and DO.
How do you define a function in Fortran
A function is a type of a procedure that only returns a single quantity. Here is the syntax for a function.
Syntax:
function name(arg1, arg2, ….)
[declarations, including those for the arguments]
[executable statements]
end function [name]
What are the basic data types in Fortran
Integer type
Real type
Complex type
Logical type
Character type
Fortran Interview Questions and Answer – Obsolescence and deletions
Obsolescent feature  Example  Status/fate in Fortran 95 

Arithmetic IFstatement 
IF (X) 10, 20, 30

Deprecated 
Noninteger DO parameters or control variables 
DO 9 X= 1.7, 1.6, 0.1

Deleted 
Shared DOloop termination or termination with a statement other than END DO or CONTINUE 
DO 9 J= 1, 10
DO 9 K= 1, 10
9 L= J + K

Deprecated 
Branching to END IF from outside a block 
66 GO TO 77 ; . . .
IF (E) THEN ; . . .
77 END IF

Deleted 
Alternate return 
CALL SUBR( X, Y, *100, *200 )

Deprecated 
PAUSE statement 
PAUSE 600

Deleted 
ASSIGN statement and assigned GO TO statement 
100 . . .
ASSIGN 100 TO H
. . .
GO TO H . . .

Deleted 
Assigned statement numbers and FORMAT specifiers 
ASSIGN 606 TO F ... WRITE ( 6, F )...

Deleted 
H edit descriptors 
606 FORMAT ( 9H1GOODBYE. )

Deleted 
Computed GO TO statement 
GO TO (10, 20, 30, 40), index

(obsolete) 
Statement functions 
FOIL( X, Y )= X**2 + 2*X*Y + Y**2

(obsolete) 
DATA statements among executable statements 
X= 27.3
DATA A, B, C / 5.0, 12.0, 13.0 /
. . .

(obsolete) 
CHARACTER* form of CHARACTER declaration 
CHARACTER*8 STRING ! Use CHARACTER(8)

(obsolete) 
Assumed character length functions 
CHARACTER*(*) STRING

(obsolete)^{[31]} 
Fixed form source code  Column 1 contains C or * or ! for comments. Columns 1 through 5 for statement numbers Any character in column 6 for continuation. Columns 73 and up ignored 
(obsolete) 
Code examples of fortran
program average ! Read in some numbers and take the average ! As written, if there are no data points, an average of zero is returned ! While this may not be desired behavior, it keeps this example simple implicit none real, dimension(:), allocatable :: points integer :: number_of_points=0.0 real :: average_points=0., positive_average=0., negative_average=0. write (*,*) "Input number of points to average:" read (*,*) number_of_points allocate (points(number_of_points)) write (*,*) "Enter the points to average:" read (*,*) points ! Take the average by summing points and dividing by number_of_points if (number_of_points > 0) average_points = sum(points) / number_of_points ! Now form average over positive and negative points only if (count(points > 0.) > 0) then positive_average = sum(points, points > 0.) / count(points > 0.) end if if (count(points < 0.) > 0) then negative_average = sum(points, points < 0.) / count(points < 0.) end if deallocate (points) ! Print result to terminal write (*,'(a,g12.4)') 'Average = ', average_points write (*,'(a,g12.4)') 'Average of positive points = ', positive_average write (*,'(a,g12.4)') 'Average of negative points = ', negative_average end program average
What Is The Difference Between If Then And Do While Statements?
IF THEN combined with GO TO statements will let you do anything you want. The DO WHILE and other DO constructs allow you to loop through certain portions of code many times without ever writing GO TO statements. This makes coding slightly simpler, definitely clearer.
What are the commonly used character functions in Fortran?
The commonly used character functions in Fortran are:
 len(string)
 index(string,sustring)
 achar(int)
 iachar(c)
 trim(string)
 scan(string, chars)
 verify(string, chars)
 adjustl(string)
 adjustr(string)
 len_trim(string)
 repeat(string,ncopy)
What is DBLE (A) function?
DBLE (A) function: It is a Numeric Function which is used to convert A to a double precision real number.