DC(1)							    DC(1)

NAME
       dc - desk calculator

SYNOPSIS
       dc [ file ]

DESCRIPTION
       Dc is an arbitrary precision arithmetic package.	 Ordinar-
       ily 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 standard 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  nega-
	     tive number.  Numbers may contain decimal points.

       +  - /  *  %  ^
	     The  top two values on the stack are added (+), sub-
	     tracted (-), multiplied (*),  divided  (/),  remain-
	     dered  (%),  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
	     register  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
	     recursion level is popped by two.	If q is	 capital-
	     ized,  the	 top value on the stack is popped and the

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DC(1)							    DC(1)

	     string execution 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
	     compared.	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 fac-
	     tor 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 main-
	     tained during multiplication, division, and exponen-
	     tiation.	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.

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

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DC(1)							    DC(1)

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

SEE ALSO
       bc(1),  which  is  a  preprocessor  for dc providing infix
       notation and a C-like syntax  which  implements	functions
       and reasonable 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.

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