BC(C)                                      UNIX System V



     Name
          bc - invokes a calculator


     Syntax
          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.
          The  -l  argument  stands  for  the  name  of  an  arbitrary
          precision math library.  The syntax for bc  programs  is  as
          follows:  L  means  the  letters  a-z, E means expression, S
          means statement.

          Comments:

              Enclosed in /* and */

          Names:

              Simple variables: L
              Array elements: L [ E ]
              The words ``base'', ``ibase'', ``obase'', and ``scale'';
              ``base'' and ``ibase'' are interchangeable.

          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 )

          Additive operators:

              +
              -

          Multiplicative operators:

              *
              /
              % (remainder)
              ^ (exponentiation)

          Unary operators:

              ++
              - -  (prefix and postfix; apply to names)

          Relational operators:

              ==
              <=
              >=
              !=
              <
              >

          Assignment operators:

              =
              =+
              =-
              =*
              =/
              =%
              =^

          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 newlines may separate statements.   Assignment
          to  scale  influences the number of digits to be retained on
          arithmetic operations in the manner of  dc(C).   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.

          bc is actually a preprocessor for dc(C),  which  it  invokes
          automatically,  unless  the  -c  (compile  only)  option  is
          present.  If the -c option is present, the dc input is  sent
          to the standard output instead.


     Example
          The following defines a function to compute  an  approximate
          value of the exponential function:

               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
                    }
               }

          The  following  prints  the  approximate   values   of   the
          exponential function of the first ten integers:

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

     Files
          /usr/lib/lib.bc     Mathematical library

          /usr/bin/dc    Desk calculator proper


     See Also
          dc(C)
          User's Guide


     Notes
          A For statement must have all three E's.

          Quit is interpreted when read, not when executed.

          Trigonometric values should be given in radians.


     (printed 8/28/89)                                  BC(C)