Fortran/Catalogs

The initial release of FORTRAN for the IBM 704 contained 32 statements, including:

• DIMENSION and EQUIVALENCE statements
• Assignment statements
• Three-way arithmetic IF statement.
• IF statements for checking exceptions (ACCUMULATOR OVERFLOW, QUOTIENT OVERFLOW, and DIVIDE CHECK); and IF statements for manipulating sense switches and sense lights
• GOTO, computed GOTO, ASSIGN, and assigned GOTO
• DO loops
• Formatted I/O: FORMAT, READ, READ INPUT TAPE, WRITE, WRITE OUTPUT TAPE, PRINT, and PUNCH
• Unformatted I/O: READ TAPE, READ DRUM, WRITE TAPE, and WRITE DRUM
• Other I/O: END FILE, REWIND, and BACKSPACE
• PAUSE, STOP, and CONTINUE
• FREQUENCY statement (for providing optimization hints to the compiler)

FORTRAN 66 includes:

• Main program, SUBROUTINE, FUNCTION, and BLOCK DATA program units
• INTEGER, REAL, DOUBLE PRECISION, COMPLEX, and LOGICAL data types
• COMMON, DIMENSION, and EQUIVALENCE statements
• DATA statement for specifying initial values
• Intrinsic and EXTERNAL (e.g., library) functions
• Assignment statement
• GOTO, assigned GOTO, and computed GOTO statements
• Logical IF and arithmetic (three-way) IF statements
• DO loops
• READ, WRITE, BACKSPACE, REWIND, and ENDFILE statements for sequential I/O
• FORMAT statement
• CALL, RETURN, PAUSE, and STOP statements
• Hollerith constants in DATA and FORMAT statements, and as actual arguments to procedures
• Identifiers of up to six characters in length
• Comment lines

FORTRAN 77 includes:

• Block IF and END IF statements, with optional ELSE and ELSE IF clauses.
• DO loop extensions, including parameter expressions, negative increments, and zero trip counts
• OPEN, CLOSE, and INQUIRE statements for improved I/O capability
• Direct-access file I/O
• IMPLICIT statement
• CHARACTER data type, with vastly expanded facilities for processing of character-based data
• PARAMETER statement for specifying constants
• SAVE statement for persistent local variables
• Generic names for intrinsic functions
• A set of intrinsics (LGE, LGT, LLE, LLT) for lexical comparison of strings, based upon the ASCII collating sequence.
• DO WHILE and END DO statements
• INCLUDE statement
• IMPLICIT NONE variant of the IMPLICIT statement
• Bit manipulation intrinsic functions, based on similar functions included in Industrial Real-Time Fortran (ANSI/ISA S61.1 (1976))