NAME

       dc - desk calculator

SYNOPSIS

       dc [ file ]

DESCRIPTION

       Dc  is  an  arbitrary precision desk calculator.  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
              0-9A-F  or  0-9a-f.  A hexadecimal number beginning with a lower case letter must be preceded by a
              zero to distinguish it from the command associated with the letter.  It  may  be  preceded  by  an
              underscore _ to input a negative number.  Numbers may contain decimal points.

       +  - /  *  %  ^
              Add  subtract  multiply divide remainder or exponentiate the top two values on the stack.  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
       Sx     Pop  the  top of the stack and store into a register named x, where x may be any character.  Under
              operation S register x is treated as a stack and the value is pushed on it.

       lx
       Lx     Push the value in register x onto the stack.  The register x is not altered.  All registers  start
              with  zero  value.  Under operation L register x is treated as a stack and its top value is popped
              onto the main stack.

       d      Duplicate the top value on the stack.

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

       f      Print the values on the stack.

       q
       Q      Exit the program.  If executing a string, the recursion level is popped by two.  Under operation Q
              the top value on the stack is popped and the string execution level is popped by that value.

       x      Treat the top element of the stack as a character  string  and  execute  it  as  a  string  of  dc
              commands.

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

       [ ... ]
              Put the bracketed text string on the top of the stack.

       <x
       >x
       =x     Pop and compare the top two elements of the stack.  Register x is executed if they obey the stated
              relation.

       v      Replace 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.

       !      Interpret the rest of the line as a shell command.

       c      Clear the stack.

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

       I      Push the input base on the top of the stack.

       o      The  top  value  on  the stack is popped and used as the number base for further output.  In bases
              larger than 10, each `digit' prints as a group of decimal digits.

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

       k      Pop the top of the stack, and use that value 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      Push the stack level onto the stack.

       Z      Replace 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.

       ; :    Used by bc for array operations.

       The scale factor set by k determines how many digits are kept to the right of the decimal point.  If s is
       the current scale factor, sa is the scale of the first operand, sb is the scale of the second, and  b  is
       the (integer) second operand, results are truncated to the following scales.

              +,-  max(sa,sb)
              *    min(sa+sb , max(s,sa,sb))
              /    s
              %    so that dividend = divisor*quotient + remainder; remainder has sign of dividend
              ^    min(sa×|b|, max(s,sa))
              v    max(s,sa)

EXAMPLES

       Print the first ten values of n!

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

SOURCE

       /src/cmd/dc.c

SEE ALSO

       bc(1), hoc(1)

DIAGNOSTICS

       x where x is an octal number: an internal error.
       `Out of headers' for too many numbers being kept around.
       `Nesting depth' for too many levels of nested execution.

BUGS

       When the input base exceeds 16, there is no notation for digits greater than F.

       Past its time.

                                                                                                      DC(1plan9)