DC(1)							      General Commands Manual							     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 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 under-
	     score _ to input a negative number.  Numbers may contain decimal points.

       +  - /  *  %  ^
	     The top two values on the stack are added (+), subtracted (-), 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 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 capitalized, the top value on the stack is
	     popped and the 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 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 out-
	     put 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 (usually the terminal) and executed.

       ; :   are used by bc for array operations.

       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 notation and a C-like syntax which implements functions and reasonable control struc-
       tures 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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