BC(1)                   GENIX Programmer's Manual                   BC(1)



      NAME
           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 )
                 }



      Printed 11/16/83                                                        1

      BC(1)                   GENIX Programmer's Manual                   BC(1)



           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  exponen-
           tial 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  automati-
           cally, unless the -c (compile only) option is present.  In this case
           the dc input is sent to the standard output instead.




      Printed 11/16/83                                                        2

      BC(1)                   GENIX Programmer's Manual                   BC(1)



      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.










































      Printed 11/16/83                                                        3