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* dc: (dc). Arbitrary precision RPN ``Desktop Calculator''.
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This file documents @command{dc}, an arbitrary precision calculator.
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Published by the Free Software Foundation, Inc.
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59 Temple Place, Suite 330
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51 Franklin Street, Fifth Floor
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Boston, MA 02110-1301 USA
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Copyright (C) 1984, 1994, 1997, 1998, 2000 Free Software Foundation, Inc.
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Copyright (C) 1984, 1994, 1997, 1998, 2000, 2005, 2006 Free Software Foundation, Inc.
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Permission is granted to make and distribute verbatim copies of
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this manual provided the copyright notice and this permission notice
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results, provided the printed document carries copying permission
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notice identical to this one except for the removal of this paragraph
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(this paragraph not being relevant to the printed manual).
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Permission is granted to copy and distribute modified versions of this
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manual under the conditions for verbatim copying, provided that the entire
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resulting derived work is distributed under the terms of a permission
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@author original manual by Richard Stallman
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@vskip 0pt plus 1filll
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Copyright @copyright{} 1994, 1997, 1998 Free Software Foundation, Inc.
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Copyright @copyright{} 1984, 1994, 1997, 1998, 2000, 2005, 2006
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Free Software Foundation, Inc.
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Published by the Free Software Foundation, @*
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59 Temple Place, Suite 330 @*
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51 Franklin Street, Fifth Floor @*
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Boston, MA 02110-1301 USA
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Permission is granted to make and distribute verbatim copies of
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this manual provided the copyright notice and this permission notice
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all error messages are written to standard error.
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To exit, use @samp{q}.
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@kbd{C-c} does not exit;
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(or whatever other keystroke your system uses to generate a @code{SIGINT})
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it is used to abort macros that are looping, etc.
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(Currently this is not true; @kbd{C-c} does exit.)
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A reverse-polish calculator stores numbers on a stack.
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Entering a number pushes it on the stack.
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Arithmetic operations pop arguments off the stack and push the results.
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To enter a number in @command{dc}, type the digits,
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To enter a number in @command{dc}, type the digits (using upper
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case letters @code{A} through @code{F} as "digits" when working
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with input bases greater than ten),
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with an optional decimal point.
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Exponential notation is not supported.
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To enter a negative number, begin the number with @samp{_}.
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@samp{-} cannot be used for this, as it is a binary operator
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for subtraction instead.
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To enter two numbers in succession,
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separate them with spaces or newlines.
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These have no meaning as commands.
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separate them with spaces or newlines;
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these have no meaning as commands.
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@node Invocation, Printing Commands, Introduction, Top
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@chapter Invocation
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to the ~ computing the characters backwards,
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and the desire to ensure that all registers wind up back
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in their original states.)
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(Details of the behavior with a number are a GNU extension.)
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(Details of the behavior with a number are a GNU extension.
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Traditional @command{dc} happened to "support" similar functionality
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for a limited range of inputs as an accidental side-effect of its
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internal representation of numbers.)
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Prints the entire contents of the stack
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to figure out what the effect of some command has been.
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All numeric output is split to fit within 70 columns, by default.
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When a number is broken up in this way, the split is indicated
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by a "\" at the end of the to-be-continued output lines.
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The column width at which output is split can be overridden
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by setting the @var{DC_LINE_LENGTH} environment variable to
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A @var{DC_LINE_LENGTH} of 0 (zero) disables the line-split
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Invalid values of @var{DC_LINE_LENGTH} are silently ignored.
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(The @var{DC_LINE_LENGTH} variable is a GNU extension.)
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@node Arithmetic, Stack Control, Printing Commands, Top
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@chapter Arithmetic
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(or number of characters, if it is a string)
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and pushes that number.
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Note that the digit count for a number does
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@emph{not} include any leading zeros,
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even if those appear to the right of the radix point.
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This may seem a bit strange at first,
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but it is compatable with historical implementations of @command{dc},
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and can be argued to be useful for computing the magnitude of a value:
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@code{dSaXLaZ-} will compute the power-of-ten multiplier
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which would be needed to shift the decimal point
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to be immediately before the leftmost non-zero digit.
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Pops a value off the stack,
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calculates the number of fraction digits it has,
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doc/dc.texi
