bc(1) General Commands Manual bc(1)
NAME
bc - arbitrary-precision arithmetic language
SYNOPSIS
[file...]
DESCRIPTION
is an interactive processor for a language that resembles C but provides unlimited-precision arithmetic. It takes input from any files
given, then reads the standard input.
Options
recognizes the following command-line options:
Compile only.
is actually a preprocessor for which invokes automatically (see dc(1)). Specifying prevents invoking dc, and sends the dc
input to standard output.
causes an arbitrary-precision math library to be predefined.
As a side effect, the scale factor is set.
Program Syntax
L a single letter in the range through
E expression;
S statement;
R relational expression.
Comments
Comments are enclosed in and
Names
Names include:
simple variables: L
array elements: L [ E ]
stacks: L
Other Operands
Other operands include:
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 )
Strings of ASCII characters enclosed in quotes ("").
Arithmetic Operators:
Arithmetic operators yield an E as a result and include:
is remainder (not mod, see below); is power).
(prefix and append; apply to names)
Relational Operators
Relational operators yield an R when used as op
Statements
E
{ S ; ... ; S }
if ( R ) S
while ( R ) S
for ( E ; R ; E ) S
null statement
break
quit
Function Definitions
define L ( L ,..., L ) {
auto L, ... , L
S; ... S
return ( E )
}
Functions in -l Math Library
Functions in the math library include:
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. Trigonometric angles are in radians where 2 pi radians = 360 degrees.
The value of a statement that is an expression is printed unless the main operator is an assignment. No operators are defined for strings,
but the string is printed if it appears in a context where an expression result would be printed. Either semicolons or new-lines can sepa-
rate statements. Assignment to scale influences the number of digits to be retained on arithmetic operations in the manner of dc(1).
Assignments to or set the input and output number radix respectively, again as defined by dc(1).
The same letter can be used simultaneously as an array, a function, and a simple variable. 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.
The operator yields the remainder at the current scale, not the integer modulus. Thus, at scale 1, is .1 (one tenth), not 1. This is
because (at scale 1) is 2.3 with .1 as the remainder.
EXAMPLES
Define a function to compute an approximate value of the exponential function:
Print approximate values of the exponential function of the first ten integers.
WARNINGS
There are currently no (AND) or (OR) comparisons.
The statement must have all three expressions.
is interpreted when read, not when executed.
parser is not robust in the face of input errors. Some simple expression such as 2+2 helps get it back into phase.
The assignment operators: and are obsolete. Any occurences of these operators cause a syntax error with the exception of which is inter-
preted as followed by a unary minus.
Neither entire arrays nor functions can be passed as function parameters.
FILES
desk calculator executable program
mathematical library
SEE ALSO
bs(1), dc(1).
tutorial in
STANDARDS CONFORMANCE
bc(1)
