bc - arbitrary-precision arithmetic language

Synopsis

Description

Files

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Bugs

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

Bcis 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-largument stands for the name of an arbitrary precision math library. The syntax forbcprograms 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

quitFunction definitions

define L ( L ,..., L ) {

auto L, ... , L

S; ... S

return ( E )

}Functions in

-lmath library

s(x) sine

c(x) cosine

e(x) exponential

l(x) log

a(x) arctangent

j(n,x) Bessel functionAll 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

scaleinfluences the number of digits to be retained on arithmetic operations in the manner ofdc(1). Assignments toibaseorobaseset 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.

Bcis actually a preprocessor fordc(1), which it invokes automatically, unless the-c(compile only) option is present. In this case thedcinput is sent to the standard output instead.

/usr/5lib/lib.bmathematical library

dc(1) desk calculator proper

dc(1)

L. L. Cherry and R. Morris, BC - An arbitrary precision desk-calculator language

No &&, ||, or ! operators.

Forstatement must have all three E's.

Quitis interpreted when read, not when executed.

Heirloom Toolchest | BC (1) | 10/11/03 |