Manual page for BC(1)
bc - arbitrary-precision arithmetic language
SYNOPSIS
bc
[
-c
] [
-l
] [ file ... ]
DESCRIPTION
Bc
is an interactive processor for a language which resembles
C but provides unlimited precision arithmetic.
It takes input from any files given, then reads
the standard input.
The
-l
argument stands for the name
of an arbitrary precision math library.
The syntax for
bc
programs is as follows;
L means letter a-z,
E means expression, S means statement.
- Comments
-
are enclosed in /* and */.
- Names
-
simple variables: L
array elements: L [ E ]
The words `ibase', `obase', and `scale'
- Other operands
-
arbitrarily long numbers with optional sign and decimal point.
( E )
sqrt ( E )
length ( E ) number of significant decimal digits
scale ( E ) number of digits right of decimal point
L ( E , ... , E )
- Operators
-
+ - * / % ^
(% is remainder; ^ is power)
++ -- (prefix and postfix; apply to names)
== <= >= != < >
= += -= *= /= %= ^=
- Statements
-
E
{ S ; ... ; S }
if ( E ) S
while ( E ) S
for ( E ; E ; E ) S
null statement
break
quit
- Function definitions
-
define L ( L ,..., L ) {
auto L, ... , L
S; ... S
return ( E )
}
- Functions in
-l
math library
-
s(x) sine
c(x) cosine
e(x) exponential
l(x) log
a(x) arctangent
j(n,x) Bessel function
All function arguments are passed by value.
The value of a statement that is an expression is printed
unless the main operator is an assignment.
Either semicolons or newlines may separate statements.
Assignment to
scale
influences the number of digits to be retained on arithmetic
operations in the manner of
dc.1
Assignments to
ibase
or
obase
set the input and output number radix respectively.
The same letter may be used as an array, a function,
and a simple variable simultaneously.
All variables are global to the program.
`Auto' variables are pushed down during function calls.
When using arrays as function arguments
or defining them as automatic variables
empty square brackets must follow the array name.
For example
scale = 20
define e(x){
auto a, b, c, i, s
a = 1
b = 1
s = 1
for(i=1; 1==1; i++){
a = a*x
b = b*i
c = a/b
if(c == 0) return(s)
s = s+c
}
}
defines a function to compute an approximate value of
the exponential function and
for(i=1; i<=10; i++) e(i)
prints approximate values of the exponential function of
the first ten integers.
Bc
is actually a preprocessor for
dc.1
which it invokes automatically, unless the
-c
(compile only)
option is present.
In this case the
dc
input is sent to the standard output instead.
FILES
/usr/lib/lib.b mathematical library
dc(1) desk calculator proper
SEE ALSO
dc(1)
L. L. Cherry and R. Morris,
BC - An arbitrary precision desk-calculator language
BUGS
No &&, ||, or ! operators.
For
statement must have all three E's.
Quit
is interpreted when read, not when executed.
Created by unroff & hp-tools.
© somebody (See intro for details). All Rights Reserved.
Last modified 11/5/97
