Instructor: Dr. Henry Neeman TAs: Ashwin Seshadri, Hisham...

CS 1313010Computer Programming

in Fortran 90& C

Instructor: Dr. Henry NeemanTAs: Ashwin Seshadri,Hisham Qureshi

Prerequisite:MATH 1523(ElementaryFunctions)or equivalent

ClassMeetings:Tues/Thurs10:30-11:45amGLCH 123Labsections:Fridays10:30am,1:30pm& 2:30pmCarson206

Note: this classis NOT for studentsmajoringin CSor enrolledin CSoptionprograms.

Syllabus for CS1313010Spring 2000Computer Programming in Fortran 90& C

Class: Tuesdays& Thursdays10:30-11:45am,GeorgeLynnCrossHall 123Instructor : Dr. HenryNeeman,Sarkeys Energy Center1252(Boyd & Jenkins)([email protected],325-5386)Officehours:Tues& Thurs12:15-1:15pm,Sarkeys Energy Center1252OR BY APPOINTMENT AT LEAST 24HOURS IN ADVANCE

Note: pleasecontactmeby e-mailunlessit’ sanemergency; pleasedon’t call theCAPSorComputerScienceofficesif youcan’t find mein my office.

Labs: Fridays10:30-11:20am(section011),1:30-2:20pm(012)or 2:30-3:20pm(013)CarsonEngineeringCenter206

TAs: AshwinSeshadri([email protected]),CarsonEngineeringCenterB18Officehoursto beannounced

HishamQureshi([email protected]),CarsonEngineeringCenterB8Officehoursto beannounced

Prerequisite: MATH 1523(ElementaryFunctions)or equivalentNote: this classis not for studentsmajoringin CSor enrolledin CSoptionprograms.

Material to becoveredProgrammingin Fortran90 (aboutthefirst half of thesemester)Programmingin C (therestof thesemester)

TextsProgramming in Fortran 90/95, 5th ed.,S.Lakshmivarahan& S.K.Dhall, 1999Availableat King Kopy (Lindsey & Jenkins)

Problem Solving & Program Design in C, 3rd ed.,J.R.Hamly & E.B.Koffman,1999

Required work7-10ProgrammingProjects(55%)WeeklyQuizzes(10%): everyTuesdayat 10:30amstartingJan25 (usuallyopenbook)Quizquestionswill betakenverbatimfrom thehomework assignedthepreviousTuesday.

MidtermExam(15%):dateto beannouncedin classFinal Exam(20%):ThursdayMay 4 8:00-10:00am

RecommendedworkReadingswill beassignedmostweeksto supplementthelectures.Weeklyhomeworkswill beassignedeveryTuesdaystartingJan18.Thesewill form thebasisfor thequizzes;they will notbecollectedor graded.

Grading: A: 90%- 100% B: 80%- 89% C: 70%- 79% D: 60%- 69% F: lessthan60%I reserve theright to curve thegradesasI seefit, but thecurvewill notbeharsherthanthis.

WebpostingsAll printedclassmaterials,includinglectureslides,homework assignmentsandprogrammingprojectdescriptions,will bepostedon theclasswebpage:

http://www.ecn.ou.edu/CS1313010/

Syllabus for CS1313010Spring 2000(continued)Computer Programming in Fortran 90& C

E-mailOccasionally, wemayneedto alerttheclasswhenanissuecomesup. You shouldcheckyour

e-mailat leastonceaweek.

ClassPoliciesCredit for programming projects

No latenessdeduction:if turnedin on time (by 11:45amon theduedate)25%deducted:if lateoneclass(by 11:45amtheclassaftertheduedate)No credit: if laterthan11:45amtheclassaftertheduedate

Helping eachotherI encourageyou to discusshomework andprogrammingprojectswith eachother. However,IT IS NOT ACCEPTABLE to copy eachother’swork. Cheatingcanresultin suspensionorexpulsion,soDON’T EVEN THINK ABOUT IT!

Help fr om usIf you havequestionsor you’rehaving troublewith thematerial,weurgeyou to cometalk tousduringofficehours,or to makeanappointment(at least24hoursin advance)to meetatothertimes,or to senduse-mail.

Working on programming projectsDo not wait until thelastminuteto startyourprogrammingprojects.Developingsoftwaretakestime,andmaydependon theavailability andreliability of systemsthatyou havenocontrolover. If thecomputersaredown thenightbeforeaduedate,don’t counton thatbuyingyouextra debuggingtime– it certainlywon’t in therealworld.

Studying for examsDo not wait until thelastminuteto startstudyingfor exams.Thebestway to ensuresuccessis to keepupwith thecoursematerial,andto askquestions.Studentswhoactively participatein lecturesandcometo office hourstypically learnandretainthemateriala lot better.

Will this be on the exam?Yes.Everythingcoveredin class,readings,labs,homeworksandprogrammingprojectsis fairgameunlessspecificallystatedotherwise.

DisabilityAny student in this course who has a disability that may prevent him or her from fullydemonstrating his or her abilities should contact the instructor personally as soon as possible sothat accommodations necessary can be made to ensure full participation and to facilitate youreducational opportunities.Be preparedto bring documentationfrom theOfficeof DisabledStudentServices.

AcademicMisconductAll casesof academicmisconductwill bereportedto theDeanof theappropriateCollegefor

adjudication.

Outline of Fortran 90 Topics

� Overview of Computing� ComputerOrganization� Languages� ProblemSolving

� Variables� DataTypes

� BasicDataTypes� 1D Arrays� DerivedDataTypes

� Assignments� Expressions

� Numeric� Non-numeric

� ControlStructures� Branching� Repetition

� Procedures� Subroutines� Functions

� Modularity� Modules� InterfaceBlocks

� Input/Output� Formatting� Files

Note: this is roughly how thispartof thesemesterwill go.

ZIP

compact disc

Hello ...

What is aComputer?

and process data.

A computer isa programmable electronic

device that can store, retrieve

Components of a Computer System

COMPUTER SYSTEM

HARDWARE SOFTWAREPhysicaldevices

Sets ofinstructions

FIRMWARESoftware thatlives on a chip

BASIC I/O

Arithmetic/LogicUnit

Registers

NETWORKING

Modem

PortInternet

MULTIMEDIA

CPU

Hardware Components

HARDWARE

Cache$1600/MB

Main

$2/MBMemory

HardDisk

CDROM

Zip/Jaz/etcDisk

MagneticTape

FloppyDisk

0.03 MB/sec$0.21/MB

1 MB/sec

100 MB/sec

ControlUnit

Proc Speed

etc

Keyboard

Mouse

Printer

Monitor

Amplifier

Speakers

etc

etc

CDROM

STORAGE INPUT/OUTPUT

etc

Joystick

Scanner

StorageSecondary

$0.007-0.04/MB8-40 MB/sec

$0.003/MB7 MB/sec

$0.07-0.14/MB2.4-7.4 MB/sec

$0.003/MB

Central Processing Unit

Registers are very expensive, because they have to be etched directlyinto the CPU.

. . .

Bit ShiftR00 << R01

AddR02 = R00 + R01

CompareR00 < R01? R03 = ~R01

Bit Invert

MultiplyR02 = R00 * R01

Registers

. . .

R00

R01

R03

R02

R63

Arithmetic/Logic Unit

Control Unit

AddR03 = R03 + R63

FetchNext

Instruction

Find Data

Memory

Fetch Datafrom

Memory

. . .

Addresses in

InstructionExecute Store

Result inMemory

IncrementInstruction

Pointer

643210 5 7

1412111098 13 15

222019181716 21 23

. . .

302827262524 29 31

34,359,738,367(32 MB)

Address

Main Memory

Cell or Location Contents

-71

. . .0 1 2 5 6 7 83 4

We can think of memory as one contiguous line of cells.

The Bus

all data travel along it.The bus is the connection from the CPU to main memory;

CPU

Main Memory

Main Memory

Bus

CPU

Yikes!

Main Memory

Bus

CPU-75

There you go!

0x12AD36BC

Bus

CPU putt putt putt ... Main Memory

Zzzzz ...

I want thecontents of

0x12AD36BC.

Bus

CPU Main Memory

Zzzzz ...

Bonk!

I’ll put it in R05.

Bus

CPU Main Memory

Zzzzz ...Bonk! -75

Load

Loading Data from Main Memory into the CPU

Load

0x12AD36BC

Cache

CPU

Main Memory

Cache

The CPU runs at, say, 500 MHz. Main Memory transfers run at, say, 100 MHz.So transferring data directly between the CPU and Main Memory is a bottleneck.

Cache is a smaller memory that runs at the same speed as the CPU.

SecondaryStorage

� Nonvolatile: datadon’t disappearwhenpower is turnedoff� Slowerandcheaperthanmainmemory� Most areportable:canbeeasilyremovedfrom yourcomputerand

takento someoneelse’s

Medium Size Speed Type Can Port- Popular? Drive Media(GB) (MB/sec) write? able? (

�) (

�/MB)

HardDisk 9-36 8.5-40.5 Mag Yes No Very 0.007-0.04/MBDVD 17 up to 13 Optic No Yes Not yet 100-300 —

Mag Tape 7 1 Mag Yes Yes Yes 100-1000 0.003DVD-RAM 5.2* 2.7 Optic Yes Yes New! 800 0.009

JazDisk 1-2 5.4-7.4 Mag Yes Yes No 350 0.07CDROM 0.63 up to 7 Optic No Yes Very 30-40 0.003CD-RW 0.63 6R/1.8W Optic Yes Yes No 170-350 0.003

SuperDisk 0.12 up to 0.7 Mag Yes Yes Not very 90-200 0.06Zip Disk 0.10 2.4 Mag Yes Yes Kind of 70-250 0.14Floppy 0.0014 0.03 Mag Yes Yes Very 10-20 0.21Cassette « 0.001 « 1 Mag Yes Yes No Historical

PaperTape « 0.001 « 1 Paper Once Yes No HistoricalPunchCard « 0.001 « 1 Paper Once Yes No Historical

Note: all numbersareapproximateasof 10 January2000.* DVD-RAM capacitywill probablygrow to about15 GB in thenext few years.

MediaTypes� Magnetic:read/write,but degradeover timeandcanbeerasedby magnets� Optical:oftencan’t write, but degradeslowly andcan’t beerasedby magnets� Paper:forgetaboutit!

Software Components

SOFTWARE

SYSTEM APPLICATIONSOFTWARESOFTWARE

You buy these. You write these.

SYSTEM SOFTWARE

COMPILERS/INTERPRETERS

C

C++

Java

Perl

Fortran 90

FUNCTIONLIBRARIES

BLAS

LAPACK

NetCDF

NCAR Graphics

LINPACK

HDF

Kinds of System Software

vi

pico

LaTeX

MS Word

TEXTPROCESSORS

SPREADSHEETS

SAS

Mathematica

Maple

Matlab

SYSTEMSMATH/STATS

Oracle

Sybase

dBASE

MS Access

DATABASES

MS Excel

Lotus

BSD

AIX

HP-UX

IRIX...

Linux

Unix

SYSTEMSOPERATING

Windows

MacOS

PalmOS

OS/2

MSDOS

HTML

csh

etc.

A SimpleFortran 90Program

scarecrow 1% cat helloworld.f90!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Program: helloworld !!!!!! Module: main !!!!!! Author: Henry Neeman 123-45-6789 !!!!!! Class: CS 1313 010 Spring 2000 !!!!!! Lab: Sec 013 Fridays 2:30pm !!!!!! Description: Prints the sentence !!!!!! ’Hello, world.’ to standard !!!!!! output. !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!PROGRAM helloworld!! Declarations!! No implicitly typed variables.IMPLICIT NONE!! Execution!! Print the sentence to stdout.PRINT *, ’Hello, world!’

END PROGRAM helloworldscarecrow 2% f90 -o helloworld helloworld.f90scarecrow 3% helloworldHello, world!

scarecrow 4%

The SameProgram Without Comments

PROGRAM helloworldIMPLICIT NONEPRINT *, ’Hello, world!’

END PROGRAM helloworld

Some Basic Elements of a Fortran Program

!!! output. !!!

!!! Class: CS 1313 010 Spring 2000 !!!

!!! Description: Prints the sentence !!!!!! ’Hello, world.’ to standard !!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!PROGRAM helloworld!! Declarations

! No implicitly typed variables.IMPLICIT NONE

!

!assumptions about any ofTells compiler to make no

the program’s variables! Execution!! Print the sentence to stdout.PRINT *, ’Hello, world!’

END PROGRAM helloworldEnd statement

Program statement

Program body

!!! Module: main !!!

Comment Block

!!! Author: Henry Neeman 123-45-6789 !!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Program: helloworld !!!

!!! Lab: Sec 013 Fridays 2:30pm !!!

Languages

� Kindsof Languages� Natural� Programming

� ConvertingBetweenProgrammingLanguages� Compilers� Interpreters� Assemblers

Kinds of Languages

NaturalLanguages� Examples:English,Chinese,Swahili, Navajo,Quechua,

Maori� Typically canbedescribedby formal rules� Might notbeboundby theserulesin everydayuse

“Any nouncanbeverbed.”“I might couldgetmeoneo’ themtherecomputers.”

� Canmix wordsandsyntaxfrom multiple languagesin onesentence“Hey, amigo,is it all right by you if I kibbitz yourchessgamewhile I watchyouranime?”

� Canbeambiguous“Whendid hesayshewasgoing?”Statethetime atwhich hesaid,“Shewasgoing.”Accordingto him, atwhattime wasshegoing?

ProgrammingLanguages� Completelydescribedandboundby formal rules� Cannotmix wordsandsyntaxfrom multiple languages� Cannotbeambiguous� WordsandsyntaxmustbeEXACTLY correct

Programming LanguageHierar chy

� High Level Languages� Examples:Fortran,C, Java,HTML� Usuallyarestandardized,socanbeusedonany kind of com-

puter� Typically aredesignedfor aparticularkind of application

e.g.,Fortranfor scientificapplications,C for operatingsys-temdesign,HTML for webpages,SASfor statistics

� AssemblyLanguage:specificto a particularCPUSetof simplecommands(e.g.,loada valuefrom a locationin memory;addtwo numbers;storea valueinto a locationin memory)

� MachineLanguage:binarycodethattheCPUunderstandsdirectly; binaryrepresentationof assemblylanguage

Converting BetweenLanguages

Compilers,interpretersandassemblersareprogramsthatturnprogramspeoplecanreadinto programscomputerscanrun.

Compiler� convertsa high level languagesourcecodeof a programinto a

machinelanguageexecutable� all at once� mustbecompletedbeforeexecutingtheprogram� Examples:Fortran,C

Interpreter� converts a high level languagesourcecodeinto machinelan-

guage� convertsandexecutesonestatementat a time� conversionandexecutionoccurwhile running� Examples:Perl,HTML, SAS,Mathematica

Assembler� convertsaCPU-specificassemblycodeinto machinelanguage� likea compiler, but low level

Our Old Friendhelloworld.f90

scarecrow 212% script helloworld.scriptScript started on Sat Jan 8 12:53:02 200scarecrow 1% cat helloworld.f90

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Program: helloworld !!!!!! Module: main !!!!!! Author: Henry Neeman 123-45-6789 !!!!!! Class: CS 1313 010 Spring 2000 !!!!!! Lab: Sec 013 Fridays 2:30pm !!!!!! Description: Prints the sentence !!!!!! ’Hello, world.’ to standard !!!!!! output. !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!PROGRAM helloworld!! Declarations!! No implicitly typed variables.IMPLICIT NONE!! Execution!! Print the sentence to stdout.PRINT *, ’Hello, world!’

END PROGRAM helloworldscarecrow 2% f90 -o helloworld helloworld.f90scarecrow 3% helloworldHello, world!

scarecrow 4% ctrl-DScript done on Sat Jan 8 12:53:22 200scarecrow 213%

Executable: helloworld

Linker/Loader

helloworld.f90F90 Source Code:

Assembly Code: helloworld.s

Assembler

Object File: helloworld.o

Compilingf90 -o helloworld helloworld.f90

compilercalled by

Automatically

Compiler

Executable: helloworld

Linker/Loader

Lexical Analysis

Parsing

Semantic Analysis

Intermediate Code Generation

Optimization

Assembly Code Generation

helloworld.f90F90 Source Code:

Assembly Code: helloworld.s

Assembler

Object File: helloworld.o

Compiler Detailsf90 -o helloworld helloworld.f90

Com

pile

r

Elementsof a Compiler

Compiler� Lexical Analyzer:identifiesprogram’s“word” elements

� Comments(ignored)� Keywords (e.g.,PROGRAM, END)� User-definedIdentifiers (e.g.,helloworld)� Operators; e.g.

arithmetic:+ - * / ** comparisons:.EQ. .NE. .LT. .LE. .GT. .GE.

arraysubscripting:( )� Parser:determinestheprogram’sgrammar� SemanticAnalyzer:determineswhattheprogramdoes� IntermediateCodeGenerator:expresses,as an assembly-like

program,whattheprogramdoes� Optimizer:makescodemoreefficient� AssemblyCodeGenerator:producesthe final assemblycode

thatrepresentswhattheprogramdoes

Assembler:convertsassemblycodeto machinecode

Linker/Loader:createsthefinal, executableversionof themachinecode

Assembly Code Generation

Lexical Analysis

Parsing

Semantic Analysis

Intermediate Code Generation

Compiling a Fortran 90 Statement

Load a into R00Load b into R01R02 = R00 + R01

Store R02 into aplusb

ld r00,ald r01,b

ad r02,r00,r01st r02,aplusb

ASSIGN(VARIABLE[aplusb],ADDITION(VARIABLE[a],VARIABLE[b]))

ASSIGN

EXPRESSION

IDENTIFIER[aplusb] EQUAL IDENTIFER[a] PLUS IDENTIFIER[b]

ADD

VARIABLEVARIABLE

VARIABLE

aplusb = a + b

AssemblyCodefor helloworld.f90on a DEC Alpha

ldah $gp, ($27)!gpdisp!1

unop

lda $gp, ($gp)!gpdisp!1

unop

ldq $27,

for_set_reentrancy($gp)!literal!2

lda $sp, -96($sp)

stq $26, ($sp)

ldq $16, $$5($gp)!literal!3

jsr $26, ($27),

for_set_reentrancy!lituse_jsr!2


mov 12, $1


ldq $27,

for_write_seq_lis($gp)!literal!5


ldah $18, 901($31)

stl $31, 8($sp)

stq $1, 72($sp)

lda $16, 8($sp)

stq $3, 80($sp)

mov -1, $17


lda $18, -256($18)

lda $20, 72($sp)

jsr $26, ($27),

for_write_seq_lis!lituse_jsr!5


ldq $26, ($sp)


mov 1, $0

lda $sp, 96($sp)

ret ($26)

AssemblyCodefor helloworld.f90on a Pentium III

pushl %ebp

movl %esp,%ebp

subl $24,%esp

movl $.C1_283,%eax

movl %eax,(%esp)

call pghpf_init

movl $14,%eax

movl %eax,8(%esp)

movl $.C1_297,%edx

movl %edx,4(%esp)

movl $.C1_300,%ecx

movl %ecx,(%esp)

call pgf90io_src_info

movl $.C1_283,%edx

movl %edx,12(%esp)

movl %edx,8(%esp)

movl $pghpf_0_+8,%eax

movl %eax,4(%esp)

movl $.C1_301,%ecx

movl %ecx,(%esp)

call pgf90io_ldw_init

movl %eax,-4(%ebp)

movl $13,%eax

movl %eax,16(%esp)

movl $.C1_304,%ecx

movl %ecx,12(%esp)

movl $.C1_283,%edx

movl %edx,8(%esp)

movl $.C1_285,%eax

movl %eax,4(%esp)

movl $.C1_298,%ecx

movl %ecx,(%esp)

call pgf90io_ldw

movl %eax,-4(%ebp)

call pgf90io_ldw_end

movl %eax,-4(%ebp)

movl $.C1_283,%eax

movl %eax,(%esp)

call pgf90_exit

leave

ret

AssemblyCodefor helloworld.f90on a DEC AlphaUsingFortran 90


unop


unop

ldq $27,


lda $sp, -96($sp)

stq $26, ($sp)


jsr $26, ($27),



mov 12, $1 ================>>>


ldq $27,


=============================>>>


ldah $18, 901($31) ==========>>>

stl $31, 8($sp)

stq $1, 72($sp) ==========>>>

lda $16, 8($sp) ==========>>>

stq $3, 80($sp) ==========>>>

mov -1, $17 ==========>>>


lda $18, -256($18) =========>>>

lda $20, 72($sp)

jsr $26, ($27),



ldq $26, ($sp)


mov 1, $0

lda $sp, 96($sp)

ret ($26)

AssemblyCodefor helloworld.f90on a DEC AlphaUsingFortran 95


unop


unop

ldq $27,


lda $sp, -96($sp)

stq $26, ($sp)


jsr $26, ($27),



ldah $18, 388($31) <<<============


ldq $27,


mov 12, $1 <<<==================


lda $18, -31489($18) <<<=========

stl $31, 8($sp)

lda $16, 8($sp) <<<=============

stq $1, 72($sp) <<<=============

mov -1, $17 <<<=============

stq $3, 80($sp) <<<=============


sll $18, 8, $18 <<<=============

lda $20, 72($sp)

jsr $26, ($27),



ldq $26, ($sp)


mov 1, $0

lda $sp, 96($sp)

ret ($26)

Machine Codefor helloworld.f90

10111101010100010101011110101001

10111010101000010101101011101000

01110101010000101011010111010001

01010100101010101101010101011010

...

How to Program in Machine LanguageDir ectly

(1) Write assemblycodefor theprogramdirectly by hand.(2) For eachassemblylanguageopcode, look up theassociatedmachinecodebit pattern.(3) On thecomputerconsole,flip switchesto matchthemachinecode.(4) Pressthe“Run” button.

Actually, on moderncomputers,programmingin machinelanguagedirectly is justaboutimpossible.

Fun and easy!

ApplicationProblem

ApplicationProblem

Executable

ApplicationProblem

ExecutableProgramming in

High Level LanguageCompiling

ApplicationProblem

Programming inHigh Level Language

Why Not Do Everything in Assembly Language?

Executableonly for

Pentiums

Programming in

Assembly LanguagePentium

Programming inMachine Language

Why Not Do Everything in Machine Language?

Not nearly as tedious or error-prone!

Incredibly tedious and ridiculously error-prone!

forDEC Alpha

Compiling Executablefor

Alphas

forPentium


Pentiums

forSGI/MIPS


SGI/MIPS

Can’t be run on any other kind of computer.May be completely obsolete in a few years.

Run

Bugs?

Bugs?

Compile

Write Program

Choose Programming Language

Construct Algorithm

Debug

The Programming Process

Yes

Yes

No

No

Formulate Problem

Get an A/Impress Your Boss/Sell for Zillions!

A LessSimpleFortran 90 Program

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Program: mynumber !!!!!! Author: Henry Neeman !!!!!! Class: CS 1313 010 Spring 2000 !!!!!! Lab: Sec 013 Fridays 2:30pm !!!!!! Description: Asks the user to pick a number within a !!!!!! range, then tells whether the user’s number !!!!!! matches the program’s. !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!PROGRAM mynumber

!! Declarations!! No implicitly typed variables.IMPLICIT NONE! Parameter constants! minnum: the user’s number should be at least this.! minnum: the user’s number should be at most this.! mynum: the number that the computer is ’thinking’ of.INTEGER,PARAMETER :: minnum = 1, maxnum = 10INTEGER,PARAMETER :: mynum = 5! Local variable! yournum: the user’s chosen number.INTEGER :: yournum!! Execution!! Tell the user the range to choose from.PRINT *, ’I’’m thinking of a number between ’, minnum, &

& ’ and ’, maxnum, ’.’! Ask for the user’s number.PRINT *, ’What number am I thinking of?’! Input the user’s number.READ *, yournum! Check whether the number is correct.IF ((yournum .LT. minnum) .OR. (yournum .GT. maxnum)) THEN! Idiotproofing: if it’s outside the range, complain.PRINT *, ’Hey! That’’s not between ’, minnum, &

& ’ and ’, maxnum, ’!’ELSE IF (yournum .EQ. mynum) THEN! If it’s correct, be amazed.PRINT *, ’That’’s amazing!’

ELSE IF (ABS(yournum - mynum) .EQ. 1) THEN! If they’re within 1, say they’re close.PRINT *, ’Close, but no cigar; I had ’, mynum, ’.’

ELSE! Otherwise, be cruel.PRINT *, ’Bzzzt! My number was ’, mynum, ’.’

ENDIFEND PROGRAM mynumber

A LessSimpleFortran 90Program’s Output

scarecrow 2% f90 -o mynumber mynumber.f90Linking:scarecrow 3% mynumberI’m thinking of a number between 1 and 10.What number am I thinking of?0Hey! That’s not between 1 and 10!

scarecrow 4% mynumberI’m thinking of a number between 1 and 10.What number am I thinking of?2Bzzzt! My number was 5.

scarecrow 5% mynumberI’m thinking of a number between 1 and 10.What number am I thinking of?4Close, but no cigar; I had 5.

scarecrow 6% mynumberI’m thinking of a number between 1 and 10.What number am I thinking of?5That’s amazing!

scarecrow 7%

Instructor: Dr. Henry Neeman TAs: Ashwin Seshadri, Hisham...

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Transcript of Instructor: Dr. Henry Neeman TAs: Ashwin Seshadri, Hisham...