# man(1) Manual page archive

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BC(1)                                                       BC(1)

NAME
bc - arbitrary-precision arithmetic language

SYNOPSIS
bc [ -c ] [ -l ] [ file ... ]

DESCRIPTION
Bc is an interactive processor for a language which resem-
bles 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 following syntax for bc pro-
grams is like that of C; L means letter a-z, E means expres-
sion, S means statement.

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 deci-
mal 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 ) {

BC(1)                                                       BC(1)

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 semi-
colons 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 respec-
tively.

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 func-
tion calls.  When using arrays as function arguments or
defining them as automatic variables empty square brackets

Bc is actually a preprocessor for dc(1), which it invokes
automatically, unless the -c (compile only) option is pre-
sent.  In this case the dc input is sent to the standard

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

BC(1)                                                       BC(1)

exponential function and

for(i=1; i<=10; i++) e(i)

prints approximate values of the exponential function of the
first ten integers.

FILES
/usr/lib/lib.b mathematical library
dc(1)          desk calculator proper