DC(1)                                                       DC(1)

     NAME
          dc - desk calculator

     SYNOPSIS
          dc [ file ]

     DESCRIPTION
          Dc is an arbitrary precision arithmetic package.  Ordinarily
          it operates on decimal integers, but one may specify an
          input base, output base, and a number of fractional digits
          to be maintained.  The overall structure of dc is a stacking
          (reverse Polish) calculator.  If an argument is given, input
          is taken from that file until its end, then from the stan-
          dard input.  The following constructions are recognized:

          number
                The value of the number is pushed on the stack.  A
                number is an unbroken string of the digits 0-9.  It
                may be preceded by an underscore _ to input a negative
                number.  Numbers may contain decimal points.

          +  - /  *  %  ^
                The top two values on the stack are added (+), sub-
                tracted (-), multiplied (*), divided (/), remaindered
                (%), or exponentiated (^).  The two entries are popped
                off the stack; the result is pushed on the stack in
                their place.  Any fractional part of an exponent is
                ignored.

          sx    The top of the stack is popped and stored into a reg-
                ister named x, where x may be any character.  If the s
                is capitalized, x is treated as a stack and the value
                is pushed on it.

          lx    The value in register x is pushed on the stack.  The
                register x is not altered.  All registers start with
                zero value.  If the l is capitalized, register x is
                treated as a stack and its top value is popped onto
                the main stack.

          d     The top value on the stack is duplicated.

          p     The top value on the stack is printed.  The top value
                remains unchanged.  P interprets the top of the stack
                as an ascii string, removes it, and prints it.

          f     All values on the stack and in registers are printed.

          q     exits the program.  If executing a string, the recur-
                sion level is popped by two.  If q is capitalized, the

     DC(1)                                                       DC(1)

                top value on the stack is popped and the string execu-
                tion level is popped by that value.

          x     treats the top element of the stack as a character
                string and executes it as a string of dc commands.

          X     replaces the number on the top of the stack with its
                scale factor.

          [ ... ]
                puts the bracketed ascii string onto the top of the
                stack.

          <x  >x  =x
                The top two elements of the stack are popped and com-
                pared.  Register x is executed if they obey the stated
                relation.

          v     replaces the top element on the stack by its square
                root.  Any existing fractional part of the argument is
                taken into account, but otherwise the scale factor is
                ignored.

          !     interprets the rest of the line as a UNIX command.

          c     All values on the stack are popped.

          i     The top value on the stack is popped and used as the
                number radix for further input.  I pushes the input
                base on the top of the stack.

          o     The top value on the stack is popped and used as the
                number radix for further output.

          O     pushes the output base on the top of the stack.

          k     the top of the stack is popped, and that value is used
                as a non-negative scale factor: the appropriate number
                of places are printed on output, and maintained during
                multiplication, division, and exponentiation.  The
                interaction of scale factor, input base, and output
                base will be reasonable if all are changed together.

          z     The stack level is pushed onto the stack.

          Z     replaces the number on the top of the stack with its
                length.

          ?     A line of input is taken from the input source (usu-
                ally the terminal) and executed.

          ; :   are used by bc for array operations.

     DC(1)                                                       DC(1)

          An example which prints the first ten values of n! is

             [la1+dsa*pla10>y]sy
             0sa1
             lyx

     SEE ALSO
          bc(1), which is a preprocessor for dc providing infix nota-
          tion and a C-like syntax which implements functions and rea-
          sonable control structures for programs.

     DIAGNOSTICS
          `x is unimplemented' where x is an octal number.
          `stack empty' for not enough elements on the stack to do
          what was asked.
          `Out of space' when the free list is exhausted (too many
          digits).
          `Out of headers' for too many numbers being kept around.
          `Out of pushdown' for too many items on the stack.
          `Nesting Depth' for too many levels of nested execution.