The six data types defined by the ANSI FORTRAN 77 specification are: INTEGER REAL DOUBLE PRECISION COMPLEX LOGICAL CHARACTER [*n], where n is between 1 and 32,767

The data type of a variable, symbolic constant, or function can be declared in a specification statement. If its type is not declared, the compiler determines a data type by the first letter of the variable, constant, or function name. A type statement can also dimension an array variable. Default requirements for these data types are listed in the following table.

Type Bytes

INTEGER 4 REAL 4 DOUBLE PRECISION 8 COMPLEX 8 LOGICAL 4 CHARACTER 1 CHARACTER*n (Maximum n is 32,767) n

Function syntax Type of return value

ABS (gen) Same as argument ACOS (real) Same as argument AIMAG (cmp8) REAL AINT (real) Same as argument ALOG (real4) REAL ALOG10 (real4) REAL AMAX0 (intA, intB [, intC] ..) REAL AMAX1 (real4A, real4B, [, real4C]...) REAL AMIN0 (intA, intB [, intC]...) REAL AMIN1 (real4A, real4B [, real4C]...) REAL AMOD (value, mod) REAL ANINT (value) REAL ASIN (real) Same as argument ATAN (real) Same as argument ATAN2 (realA, realB) Same as argument CABS (cmp) Same as argument; COMPLEX returns REAL CCOS (cmp8) COMPLEX CHAR (int) CHARACTER CLOG (cmp8) COMPLEX CMPLX (genA [, genB]) COMPLEX CONJG (cx8value) COMPLEX

COS (gen) Same as argument COSH (real) Same as argument CSIN (cmp8) COMPLEX CSQRT (cx8value) COMPLEX DABS (r8value) DOUBLE PRECISION DACOS (dbl) DOUBLE PRECISION DASIN (dbl) DOUBLE PRECISION DATAN (dbl) DOUBLE PRECISION DATAN2 (dblA, dblB) DOUBLE PRECISION DBLE (value) DOUBLE PRECISION DCOS (dbl) DOUBLE PRECISION DCOSH (dbl) DOUBLE PRECISION DDIM (dblA, dblB) DOUBLE PRECISION DEXP (dbl) DOUBLE PRECISION DIM (genA, genB) Same as arguments DINT (rvalue) DOUBLE PRECISION DLOG (dbl) DOUBLE PRECISION DLOG10 (dbl) DOUBLE PRECISION DMAX1 (dblA, dblB[, dblC]...) DOUBLE PRECISION DMIN1 (dblA, dblB[dblC]...) DOUBLE PRECISION DMOD (value, mod) DOUBLE PRECISION

DNINT (dbl) DOUBLE PRECISION DPROD (real4A, real4B) DOUBLE PRECISION DREAL (cxvalue) DOUBLE PRECISION DSIGN (dblA, dblB) DOUBLE PRECISION DSIN (dbl) DOUBLE PRECISION DSINH (dbl) DOUBLE PRECISION DSQRT (rvalue) DOUBLE PRECISION DTAN (dbl) DOUBLE PRECISION DTANH (dbl) DOUBLE PRECISION EXP (gen) Same as argument FLOAT (ivalue) REAL IABS (int) Same as argument ICHAR (char) INTEGER IDIM (intA, intB)INTEGER IDINT (dbl) INTEGER IDNINT (dbl) INTEGER IFIX (real4) REAL INDEX (charA, charB) INTEGER INT (gen) INTEGER ISIGN (intA, intB) INTEGER LEN (char) INTEGER

LGE (charA, charB) LOGICAL LGT (charA, charB) LOGICAL LLE (charA, charB) LOGICAL LLT (charA, charB) LOGICAL LOG (gen) Same as argument LOG10 (real) Same as argument MAX (genA, genB[, genC]...) INTEGER or REAL MAX0 (intA, intB[, intC]...) INTEGER MAX1 (realA, realB[, realC]...) INTEGER MIN (genA, genB[, genC]...) INTEGER or REAL MIN0 (intA, intB[, intC]...) INTEGER MIN1 (realA, real[, real]...) INTEGER MOD (genA, genB) REAL NINT (real) INTEGER REAL (gen) REAL SIGN (genA, genB) INTEGER or REAL SIN (gen) Same as argument SINH (real) Same as argument SNGL(dbl) REAL SQRT (gen) Same as argument TAN (real) Same as argument TANH (real) Same as argument

FORTRAN Statements

ASSIGN label TO variable

BACKSPACE {unitspec | ([UNIT=]unitspec [, ERR=errlabel] [, IOSTAT=iocheck])}

BLOCK DATA [blockdataname]

CALL sub [([actuals])]

CHARACTER [*chars] vname [

*length][(dim)]

[, vname [*length][(dim)]

CLOSE ([UNIT=]unitspec [, ERR=errlabel] [, IOSTAT=iocheck] [, STATUS=status])

COMMON [/[cname] /] nlist,]/[cname] /nlist ]...

COMPLEX vnam [(dim)] [,vname [(dim)]]...

CONTINUE

DATA nlist /clist/ [ [,] nlist /clist/]...

DIMENSION array ([lower:]upper [, {[lower:]upper ])

DO [label [,] ] dovar = start, stop [, inc]

DOUBLE PRECISION vname [(dim)] [,vname [(dim)] ]...

ELSE statementblock

ELSE IF (expression) THEN statementblock

END

END IF

ENDFILE {unitspec | ([UNIT=] unitspec [, ERR=errlabel] [, IOSTAT=iocheck] )}

ENTRY ename [ ( [formal [,formal ]...])] EQUIVALENCE (nlist) [, (nlist)]...

EXTERNAL name [,name ]...

FORMAT [editlist]

[ type] FUNCTION func ([formal ][,formal ]...)

GOTO variable [ [,] (labels)]

GOTO (labels) [,] n

GOTO label

IF (expression) label1, label2, label3

IF (expression) statement

IF (expression) THEN statementblock1 [ELSE IF (expression) THEN statementblock2]... [ELSE statementblock3] END IF

IMPLICIT type (letters) [, type (letters)]... INQUIRE ({[UNIT=]unitspec | FILE=file} [ , ACCESS=access] [ , BLANK=blank] [ , DIRECT=direct] [ , ERR=errlabel] [ , EXIST=exist] [ , FORM=form] [ , FORMATTED=formatted] [ , IOSTAT=iocheck] [ , NAME=name] [ , NAMED=named] [ , NEXTREC=nextrec] [ , NUMBER=num] [ , OPENED=opened] [ , RECL=recl] [ , SEQUENTIAL=seq] [ , UNFORMATTED=unformatted])

INTEGER vname [(dim)] [ , vname [ (dim)] ] ...

INTRINSIC names

LOGICAL vname [(dim)] [, vname [(dim)]]...

OPEN ([UNIT=]unitspec [ , ACCESS=access] [ , BLANK=blanks] [ , ERR=errlabel] [ , FILE=file] [ , FORM=form] [ , IOSTAT=iocheck] [ , RECL=recl] [ , STATUS=status])

PARAMETER (name=constexpr [, name=constexpr]...)

PAUSE [prompt]

PRINT { *, | formatspec | } [, iolist]

PROGRAM program-name

READ { formatspec, | ([UNIT=] unitspec [ , [FMT=] formatspec] [ , END=endlabel ] [ , ERR=errlabel ] [ , IOSTAT=iocheck] [ , REC=rec])} iolist

REAL vname [(dim)] [, vname [(dim)]]...

RETURN [ordinal]

REWIND { unitspec | ([UNIT=]unitspec [ , ERR=errlabel] [ , IOSTAT=iocheck])}

SAVE [names]

STOP [ message]

SUBROUTINE subr [([ formal [ , formal ]...])]

WRITE ([UNIT=] unitspec [ , [ FMT=] formatspec] [ , ERR=errlabel] [ , IOSTAT=iocheck] [ , REC=rec] ) iolist