Fortran
The first version of FORTRAN (1957) and its successor FORTRAN II (1958) did not have logical values or operations; even the conditional IF
statement took an arithmetic expression and branched to one of three locations according to its sign; see arithmetic IF. FORTRAN IV (1962), however, followed the ALGOL 60 example by providing a Boolean data type (LOGICAL
), truth literals (.TRUE.
and .FALSE.
), Boolean-valued numeric comparison operators (.EQ.
, .GT.
, etc.), and logical operators (.NOT.
, .AND.
, .OR.
). In FORMAT
statements, a specific control character ('L
') was provided for the parsing or formatting of logical values.
Read more about this topic: Boolean Data Type