BC(1)                    DOMAIN/IX SYS5                     BC(1)



NAME
     bc - arbitrary-precision arithmetic language

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

DESCRIPTION
     Bc is an interactive processor for a language that resembles
     C, but provides unlimited precision arithmetic.  It takes
     input from any file given, then reads the standard input.

     Bc is actually a preprocessor for dc(1), which it usually
     invokes automatically.

PROGRAM SYNTAX
     The syntax for bc programs is shown below (L = letters a-z,
     E = expression, S = statement).

     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.  As in dc(1), an
     assignment to scale influences the number of digits to be
     retained on arithmetic operations.  An assignment to ibase
     or obase sets 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
     function calls.  When using arrays as function arguments or
     defining them as automatic variables, empty square brackets
     must follow the array name.

     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 signs and
           decimal points
           ( E )
           sqrt ( E )
           length ( E )   Number of significant decimal digits
           scale ( E )    Number of digits right of decimal point
           L ( E , ... , E )




Printed 12/4/86                                              BC-1

BC(1)                    DOMAIN/IX SYS5                     BC(1)



     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 )
           }

     Functions in 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.

OPTIONS
     -c        Compile only. Send the input of dc(1) to standard
               output.

     -l name   Specify name as the name of an arbitrary precision
               math library to be used.

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



BC-2                                              Printed 12/4/86

BC(1)                    DOMAIN/IX SYS5                     BC(1)



               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 for
     the first ten integers.

CAUTIONS
     The double ampersand (&&) and double pipe (||) characters
     are not yet valid operators for use with bc.

     A for statement must have all three E's.

     Quit is interpreted when read, but not when executed.

FILES
     /usr/lib/lib.b mathematical library

     /usr/bin/dc    desk calculator proper

RELATED INFORMATION
     dc(1).
























Printed 12/4/86                                              BC-3