BC(C)                    XENIX System V                     BC(C)



     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 ``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 )

          Additive operators:

              +
              -

          Multiplicative operators:

              *
              /
              % (remainder)
              ^ (exponentiation)









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     BC(C)                    XENIX System V                     BC(C)



          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 )
              }













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     BC(C)                    XENIX System V                     BC(C)



          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
                    }
               }






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     BC(C)                    XENIX System V                     BC(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)
          The XENIX 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.



































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