Chapter Defining Variables ARRAYS, and Memory | Intel fortran-80

CHAPTER 3

DEFINING VARIABLES,

ARRAYS, AND MEMORY

This chapter describes the statements used to specify the types and lengths associated with symbolic names, how to assign values to these symbols, .how to structure memory, and how to assign values to a block of memory. The statements described are:

•Type statements: REAL, INTEGER, LOGICAL, CHARACTER, IMPLICIT

•Array definition statement: DIMENSION

•Assignment statements: arithmetic, logical, and character assignment,

ASSIGN, DATA

•Memory definition statements: COMMON , EQUIVALENCE, BLOCK DATA

3.1Type Statements

The type statements REAL, INTEGER, LOGICAL, and CHARACTER are used to confirm or override the type implied by a symbolic name (i.e., the convention that names beginning with the letters I-N refer to integers-Section 2.2.2.1). The conven- tion itself can be confirmed or changed by the IMPLICIT statement.

Type statements can also specify data length pr array dimension information.

Specifying the symbolic name of a variable, array, external function, or statement function in a type statement establishes the type of that name for all appearances in the program unit. The type of a name cannot be specified explicitly more than once in a program unit. Program names and subroutine names cannot appear in a type statement.

3.1.1 REAL Type Statement

The REAL type statement has the format:

REAL name [,name] ...

where 'name' is the symbolic name of a real variable, array, array declarator, func- tion, or dummy procedure.

Examples:

REAL TEMP

REAL NUMB1, NUMB2, NUMB3

C REAL OVERRIDES IMPLICITTYPING OF NUMB=INTEGER

3.1.2 INTEGER Type Statement

The INTEGER type statement has the format:

INTEG ER.fm!@ti£;l) name [,name] ...

3-1

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Intel fortran-80 Chapter Defining Variables ARRAYS, and Memory, Type Statements, Real Type Statement, Real name ,name

Contents

FORTRAN-SO Programming Manual Prompt Preface Page Contents Chapter Programming Guidelines Illustrations Glossary FORTRAN-SO Chapter Introduction to Fortran An Introductory ExampleComment Lines Output Statements Type StatementInput Statements Value Assignment Statement Nonexecutable Statements Summary Of FORTRAN·SO StatementsProgram Termination Executable Statements Format Order of Statements Program Units and Procedures Chapter Fortran ConceptsFortran Program Structure Prog RAM Statement Statements and LinesProgram name = 8*C + D* *2/E Fortran Statement ElementsCharacter Set #Pol.1ndSign B52 Constants and Variables Arithmeticoverflow Error Murphyslaw Sl#d ...b Where+64101 #14010 #4567Q +#AF2CH Sqdiag = Sqrt 2*S* *2 Sperim = 4*S Sqarea = S**2 Relational Expressions OP1 NOT.OP1 True False False True If Numb .GT Stop If Pname .EO. Gehrigprint 20, PNAME, AVGEXP1 operator EXP2 EXP1 EXP2 operator Stop OP1 OP2 OP1 .NEQV. OP2 Precedence of Operators 15/3 + 18/9 = 5 + 2 = 15/3 + 18/9 = 15/3 + 2 = 15/5 = Scope of Symbols Notational Conventions Call sub arg,argCall ROUT1A, 3.72 Page Integer Type Statement Chapter Defining Variables ARRAYS, and MemoryType Statements Real Type Statement Va,luernustueiA, Qp4 Logical Type Statement Len Aryd* len Character * len, name ,name Character TICTAC3,3 Logical ,3,3 Array DefinitionImplicit REALA-B, D-H, Character C Implicit Integer I-N, Logical O-l ARRAY3,MI00LE,THIRD Dimension StatementLogical Table Integer Array Dimension ,3, ARRAY3,3,3 Kinds of Array Declarators Ary s ,s Dimension ,3Properties of Arrays Referencing Array Elements ARRAY2,6 = a Arrayi + J, 3 = ARRAYM,M + N,M-N = a + SQRT8 Assignment Statements Arithmetic Assignment Statement CHARACTER*10 NAMES4, MGR MGR = Stengel NAMES1 = Gehrig = expLogical FLAG, ,3 = char R*c Data StatementAssign stlTO name Assign 1010 to LOOP1 Goto LOOP1 Equivalence Statement Data I,J,K/10,20,301Data Zeros 110*0/1,J,K 110,20,301 &NAMES2 Iotti Fpnumb Common StatementReal Fpnumb Array List Block Data Subprograms Block Data Statement Block Data nameZEROS/1 0 Computed GO to Statement Program Execution ControlsTransferring Program Oontrol Unconditional GO to Statement Assigned GO to Statement Arithmetic if StatementAssign 10TO Start Gotostart Assign 999 to Done If Done Pause If .NOT. Done GO to Start Logical if Statement6 IF, Else IF, and Else Blocks Done = a * *2 .GT **2 Else if exp then Block if StatementElse if Statement If exp then Else if Flag .EO then Write 6,40 Fedtax Else StatementEND if Statement If Flag .EO then Loop Control Statements Operation of a do LoopDo Statement CHARACTER*12 Pname Program Termination StatementsContinue Statement Continue Pause BREAK12 Pause StatementStop Statement Pause Chapter Functions and Subroutines Intrinsic and Statement FunctionsIntrinsic Functions Intrinsic Sqrt Intrinsic EXP, LOG, LOG10 Intri Nsic StatementStatement Functions Intrinsic tunc ,tunc 156.8 Function Statement External Procedures Total = Total + Arrayk 100CONTINUE Return END SubroutinesFunction Subprogram Limitations Do 100 K = 1 SU Brouti N E subdum,dum Subroutine StatementRetu RN Statement Program CALL.. Subroutine External proe ,proe Save StatementExternal Statement Save lebl ,Iebl Call Statement Arguments And Common Blocks Revisited Common Blocks Dummy And Actual ArgumentsAssociation Of Arguments Agreement Of Argument Lengths Function FA,B,C FX, YPage File Properties Chapter INPUT/OUTPUTRecords, Files, And Units Record Properties External And Internal Files File ExistenceFile Name File Position Unit Properties File Access 1.2 1/0 Status Specifier File-Handling StatementsOpen Statement Unit Specifier Error Specifier File Name SpecifierFile Status Specifier Formatting Specifier Access Method SpecifierAccess = Sequential Access = SEQUENTIAL,FORM = Formatted Blank = blnk Open 3, FILE=CARDS,STATUS=NEW,ACCESS=DIREcrBlank Specifier Form = FORMATTED,RECL=80 Close 3, IOSTAT= ERRFLG, ERR= Close StatementOpening a Connected Unit Close close-list Backspace Backspace StatementRewi N D Statement File Disposition Specifier Endfile arg-list Data-Transfer 1/0 StatementsEndfile Statement Read Statement Control Information List Read 2 PNAME, AB, HitsFMT =f Read 2,25 PNAME, AS, Hits Read 25, Pnam E, AS, HitsAssign 25 to Infmt Read 2,INFMT Pname Input List Implied-DO ListWrite ctl-list out-list Print 120, PNAME, AVG Formatted And Unformatted Data TransferPrint Statement Unformatted Data Transfer Printing Formatted Records Formatted Data Transfer Stl Format flist Format Statement Is Ff OY1 Y2 Y1 Y2 Y3± Y1 Y2···Ye Z5editdesctiptor Either a sjgu ora letter indicatingthebas¢ Write 7,100 Itstno Format Thisis the Test NUMBER,2X Write 7,100Format 1X, A12, 4X, F4.3 DollytSigfjl$ijitrrrg· Read 2,50 INTNUM, Fpnum Format A20, $ List·Directed FormattingList-Directed Input Paint 25, Pname List-Directed Output Page Program Documentation Problem DefinitionChapter Programming Guidelines Program Development Refining The Problem Definition Level OneLevel Two Write unit, 60 EMP, HRS, GRPAY, Netpay Format flist Otherwise Print Employee Data and Update Totals ElseFinal Coding Level Three Crossing Unit Lines Fortran CodingFunctions And Subroutines GO to Statement PI = ReferencesReminders = 2217*r* *2 Programming Guidelines Appendix a FORTRAN-80 Statement Summary Statement SequenceStatement Summary ERR = stl Stat Iostat =Stname Status = Continue execution provides END FORTRAN-80 FORTRAN-80 FORTRAN-SO Iostat = Return Rewind Statement Subroutine Statement Category Executable Text Reference .2.2 Intrinsic Function Summary Appendix B Intrinsic Functions Category Function Arguments Int-12.8 = Page Hollerith Constants In Data Statements Appendix C Hollerith Data TypeHollerith As a Data Type Hollerith Constant AEditing Of Hollerith Data Hollerith Format Specification Appendix D Extensions to Ansi Fortran Standard Extensions To 1977 SubsetNonstandard Extensions To 1977 Fortran Differences From 1966 Fortran More Specific Semantics Than 1977 Fortran FORTRAN-80 Page Ascii Codes Ascii CodesPage Appendix F 8080/8085 Processor Dependencies Processor Limitations On LanguageCompiler Extensions $REENTRANT Where the $must be in columnCall Input port, var Call Output port, exp Call INPUT1, TEST1 Call OUTPUT2 $0077 Default Data LengthsInterpretation of do Statements Including Source Files F1MYPROG UNIT4 LP, Unit 5 Fosysin Unit n = device Index Block Data Function Subroutine Index Page Page Page Inter Postage will be paid by Addressee WED Like Your Comments Request for Readerscomments 111111 Page Inter