z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

Options
Numbers
Identifiers
bc supports the following options.
–i Puts bc into interactive mode with a displayed prompt. In this mode, bc
displays a prompt, which is “:”—waiting for input. In addition, it handles
errors somewhat differently. Normally, when bc encounters an error while
processing a file, the interpreter displays the error message and exits. In
interactive mode, the interpreter displays the message and returns to the
prompt mode to allow debugging.
–l Loads a library of standard mathematical functions before processing any
other input. This library also sets the scale to 20. For a description of the
functions in the –l library, see Built-in Functions.
Numbers consist of an optional minus (−) sign or an optional plus (+) sign followed
by a sequence of zero or more digits, followed by an optional decimal point (.),
followed by a sequence of zero or more digits. Valid digits are 0 through 9, and the
hexadecimal digits A through F. The uppercase letters represent the values from 10
through 15. There must be at least one digit, either before or after the decimal point.
If not, bc interprets the decimal point as the special variable ..
A number can be arbitrarily long and can contain spaces. Here are some valid
numbers with an input base of 10:
0 0. .0 -3.14159 +09. -12 1 000 000
Here are some valid numbers with an input base of 16 (ibase=16):
0 FF FF.3 -10.444 A1
See Bases for more information.
A final point is that you cannot break up numbers with commas; you can write
1000000 or 1 000 000, but 1,000,000 results in an error message.
Identifiers can include sequences containing any number of letters, digits, or the
underscore (_) character but must start with a lowercase letter. Spaces are not
allowed in identifiers.
In the POSIX locale, valid identifiers can include sequences containing any number
of letters, digits, or the underscore (_) character but must start with a lowercase
letter, as defined by the current locale.
For other locales, the character map for that locale determines which characters are
valid in an identifier. If you want identifiers to be portable between locales, use
characters from the POSIX character set. The use of identifiers longer than one
character is an extension of this implementation. Identifiers are used as names for
variables, functions, or arrays:
v A variable holds a single numeric value. You can declare variables that are local
to a function using the auto statement. (See Functions). All other variables are
global and you can use them inside any function or outside all functions. You do
not need to declare global variables. bc creates variables as it requires them,
with an initial value of zero. (Remember that there is also the special variable .
[dot], which contains the result of the last calculation.)
bc
Chapter 2. Shell command descriptions 51