4.4BSD/usr/share/man/cat1/dc.0

DC(1)                        BSD Reference Manual                        DC(1)

NNAAMMEE
     ddcc - desk calculator

SSYYNNOOPPSSIISS
     ddcc [file]

DDEESSCCRRIIPPTTIIOONN
     DDcc 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
     ddcc is a stacking (reverse Polish) calculator.  If an argument is given,
     input is taken from that file until its end, then from the standard in-
     put.  The following constructions are recognized:

     _n_u_m_b_e_r
           The value of the number is pushed on the stack.  A number is an un-
           broken 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 (-), mul-
           tiplied (*), 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.

     ss_x    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 treat-
           ed as a stack and the value is pushed on it.

     ll_x    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.

     dd     The top value on the stack is duplicated.

     pp     The top value on the stack is printed.  The top value remains un-
           changed.  _P interprets the top of the stack as an ascii string, re-
           moves it, and prints it.

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

     qq     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.

     xx     treats the top element of the stack as a character string and exe-
           cutes it as a string of ddcc commands.

     XX     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.  Regis-
           ter _x is executed if they obey the stated relation.

     vv     replaces the top element on the stack by its square root.  Any ex-
           isting 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.

     cc     All values on the stack are popped.

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

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

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

     kk     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 ex-
           ponentiation.  The interaction of scale factor, input base, and
           output base will be reasonable if all are changed together.

     zz     The stack level is pushed onto the stack.

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

     ??     A line of input is taken from the input source (usually the termi-
           nal) and executed.

     ;; ::   are used by bc for array operations.

     An example which prints the first ten values of nn!!:

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

SSEEEE AALLSSOO
     bc(1),  which is a preprocessor for ddcc providing infix notation and a C-
     like syntax which implements functions and reasonable control structures
     for programs.

HHIISSTTOORRYY
     The ddcc command appeared in Version 6 AT&T UNIX.

DDIIAAGGNNOOSSTTIICCSS
     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.

AT&T 7th Edition                 June 6, 1993                                2