FORTRAN 77 Language Reference

Character Set

The character set consists of the following:

Special characters--The following table shows the special characters that are used for punctuation:

Table 1-1 Special Character Usage


Character	Name	Usage
Space	Space	Ignored in statements, except as part of a character constant
Tab	Tab	Establish the line as a tab-format source line `@`
`=`	Equals	Assignment
`+`	Plus	Add, unary operator
`-`	Minus	Subtract, unary operator
`*`	Asterisk	Multiply, alternate returns, comments, exponentiation, `stdin`, `stdout`, list-directed I/O
`/`	Slash	Divide, delimit data, labeled commons, structures, end-of-record
`( )`	Parentheses	Enclose expressions, complex constants, equivalence, parameter, or implicit groups, formats, argument lists, subscripts
`,`	Comma	Separator for data, expressions, complex constants, equivalence groups, formats, argument lists, subscripts
`.`	Period	Radix point, delimiter for logical constants and operators, record fields
`'`	Apostrophe	Quoted character literals
`"`	Quote	Quoted character literals, octal constants `@`
`$`	Dollar sign	Delimit namelist input, edit descriptor, directives `@`
`!`	Exclamation	Comments `@`
`:`	Colon	Array declarators, substrings, edit descriptor
`%`	Percent	Special functions: `%REF`, `%VAL`, `%LOC` @
`&`	Ampersand	Continuation, alternate return, delimit namelist input; use in column 1 establishes the line as a tab-format source line @
`?`	Question mark	Request names in namelist group@
`\`	Backslash	Escape character @
< >	Angle brackets	Enclose variable expressions in formats @

Note the following usage and restrictions:

Uppercase or lowercase is not significant in the key words of FORTRAN statements or in symbolic names. The -U option of f77 makes case significant in symbolic names.@

Most control characters are allowed as data even though they are not in the character set. The exceptions are: Control A, Control B, Control C, which are not allowed as data. These characters can be entered into the program in other ways, such as with the char() function.@

Any ASCII character is valid as literal data in a character string. @

For the backslash (\) character, you may need to use an escape sequence or use the -xl compiler option. For the newline (\n) character, you must use an escape sequence. See also Table 2-3.