bc(1)                                                          bc(1)


       NAME
             bc - arbitrary-precision arithmetic language

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

       DESCRIPTION
             bc 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.  bc is
             actually a preprocessor for the desk calculator program dc,
             which it invokes automatically unless the -c option is
             present.  In this case the dc input is sent to the standard
             output instead.  The options are as follows:

             -c    Compile only.  The output is sent to the standard
                   output.

             -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
                   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)
                   ==   <=   >=   !=   <   >
                   =   =+   =-   =*   =/
                   =%   =^


                           Copyright 1994 Novell, Inc.               Page 1

      bc(1)                                                          bc(1)


            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 new-lines may separate statements.  Assignment to scale
            influences the number of digits to be retained on arithmetic
            operations in the manner of dc.  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.

      EXAMPLES
                  scale = 20
                  define e(x){
                        auto a, b, c, i, s


                          Copyright 1994 Novell, Inc.               Page 2

       bc(1)                                                          bc(1)


                         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.

       FILES
             /usr/lib/lib.b           mathematical library
             /usr/bin/dc              desk calculator proper

       REFERENCES
             dc(1)

       NOTICES
             The bc command does not recognize the logical operators && and
             ||.

             The for statement must have all three expressions (E's).

             The quit statement is interpreted when read, not when
             executed.

             For certain operations, the value of scale might be calculated
             to be larger than the current specified scale value.  When you
             set scale to a large value, take this into account when
             performing operations that could overflow the specified scale
             value.







                           Copyright 1994 Novell, Inc.               Page 3