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<head>
<title>dc(1) - Plan 9 from User Space</title>
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<tr><td width=20><td>
<tr><td width=20><td><b>DC(1)</b><td align=right><b>DC(1)</b>
<tr><td width=20><td colspan=2>
<br>
<p><font size=+1><b>NAME </b></font><br>
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dc – desk calculator<br>
</table>
<p><font size=+1><b>SYNOPSIS </b></font><br>
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<tt><font size=+1>dc</font></tt> [ <i>file</i> ]<br>
</table>
<p><font size=+1><b>DESCRIPTION </b></font><br>
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<i>Dc</i> 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 <i>dc</i> 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:<br>
number<br>
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The value of the number is pushed on the stack. A number is an
unbroken string of the digits <tt><font size=+1>0−9A−F</font></tt> or <tt><font size=+1>0−9a−f</font></tt>. 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 <tt><font size=+1>_</font></tt> to
input a negative number. Numbers may contain decimal points.<br>
</table>
<tt><font size=+1>+ − / * % ^<br>
</font></tt>
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Add <tt><font size=+1>+</font></tt>, subtract <tt><font size=+1>−</font></tt>, multiply <tt><font size=+1>*</font></tt>, divide <tt><font size=+1>/</font></tt>, remainder <tt><font size=+1>%</font></tt>, or exponentiate
<tt><font size=+1>^</font></tt> 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.<br>
</table>
<tt><font size=+1>s</font></tt><i>x<br>
</i><tt><font size=+1>S</font></tt><i>x</i> Pop the top of the stack and store into a register named <i>x</i>,
where <i>x</i> may be any character. Under operation <tt><font size=+1>S</font></tt> register <i>x</i> is
treated as a stack and the value is pushed on it.<br>
<tt><font size=+1>l</font></tt><i>x<br>
</i><tt><font size=+1>L</font></tt><i>x</i> Push the value in register <i>x</i> onto the stack. The register <i>x</i>
is not altered. All registers start with zero value. Under operation
<tt><font size=+1>L</font></tt> register <i>x</i> is treated as a stack and its top value is popped
onto the main stack.<br>
<tt><font size=+1>d</font></tt> Duplicate the top value on the stack.<br>
<tt><font size=+1>p</font></tt> Print the top value on the stack. The top value remains unchanged.
<tt><font size=+1>P</font></tt> interprets the top of the stack as an text string, removes it,
and prints it.<br>
<tt><font size=+1>f</font></tt> Print the values on the stack.<br>
<tt><font size=+1>q<br>
Q</font></tt> Exit the program. If executing a string, the recursion level
is popped by two. Under operation <tt><font size=+1>Q</font></tt> the top value on the stack
is popped and the string execution level is popped by that value.<br>
<tt><font size=+1>x</font></tt> Treat the top element of the stack as a character string and
execute it as a string of <i>dc</i> commands.<br>
<tt><font size=+1>X</font></tt> Replace the number on the top of the stack with its scale factor.<br>
<tt><font size=+1>[ ... ]<br>
</font></tt>
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Put the bracketed text string on the top of the stack.<br>
</table>
<tt><font size=+1><</font></tt><i>x<br>
</i><tt><font size=+1>></font></tt><i>x<br>
</i><tt><font size=+1>=</font></tt><i>x</i> Pop and compare the top two elements of the stack. Register
<i>x</i> is executed if they obey the stated relation.<br>
<tt><font size=+1>v</font></tt> 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.<br>
<tt><font size=+1>!</font></tt> Interpret the rest of the line as a shell command.<br>
<tt><font size=+1>c</font></tt> Clear the stack.<br>
<tt><font size=+1>i</font></tt> The top value on the stack is popped and used as the number base
for further input.<br>
<tt><font size=+1>I</font></tt> Push the input base on the top of the stack.<br>
<tt><font size=+1>o</font></tt> 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.<br>
<tt><font size=+1>O</font></tt> Push the output base on the top of the stack.<br>
<tt><font size=+1>k</font></tt> 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.
<tt><font size=+1>z</font></tt> Push the stack level onto the stack.<br>
<tt><font size=+1>Z</font></tt> Replace the number on the top of the stack with its length.<br>
<tt><font size=+1>?</font></tt> A line of input is taken from the input source (usually the terminal)
and executed.<br>
<tt><font size=+1>; :</font></tt> Used by <i>bc</i> for array operations.
<table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table>
The scale factor set by <tt><font size=+1>k</font></tt> determines how many digits are kept
to the right of the decimal point. If <i>s</i> is the current scale factor,
<i>sa</i> is the scale of the first operand, <i>sb</i> is the scale of the second,
and <i>b</i> is the (integer) second operand, results are truncated to
the following scales.<br>
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<tt><font size=+1>+</font></tt>,<tt><font size=+1>− </font></tt> max(<i>sa,sb</i>)<br>
<tt><font size=+1>* </font></tt> min(<i>sa</i>+<i>sb</i> , max(<i>s,sa,sb</i>))<br>
<tt><font size=+1>/ </font></tt><i> s<br>
</i><tt><font size=+1>% </font></tt> so that dividend = divisor*quotient + remainder; remainder has
sign of dividend<br>
<tt><font size=+1>^ </font></tt> min(<i>sa</i>×|<i>b</i>|, max(<i>s,sa</i>))<br>
<tt><font size=+1>v </font></tt> max(<i>s,sa</i>)<br>
</table>
</table>
<p><font size=+1><b>EXAMPLES </b></font><br>
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Print the first ten values of <i>n</i>!<br>
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<tt><font size=+1>[la1+dsa*pla10>y]sy<br>
0sa1<br>
lyx<br>
</font></tt>
</table>
</table>
<p><font size=+1><b>SOURCE </b></font><br>
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<tt><font size=+1>/usr/local/plan9/src/cmd/dc.c<br>
</font></tt>
</table>
<p><font size=+1><b>SEE ALSO </b></font><br>
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<a href="../man1/bc.html"><i>bc</i>(1)</a>, <a href="../man1/hoc.html"><i>hoc</i>(1)</a><br>
</table>
<p><font size=+1><b>DIAGNOSTICS </b></font><br>
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<i>x</i> <tt><font size=+1>is unimplemented</font></tt>, where <i>x</i> is an octal number: an internal error.<br>
‘Out of headers’ for too many numbers being kept around.<br>
‘Nesting depth’ for too many levels of nested execution.<br>
</table>
<p><font size=+1><b>BUGS </b></font><br>
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When the input base exceeds 16, there is no notation for digits
greater than <tt><font size=+1>F</font></tt>.
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Past its time.<br>
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<!-- TRAILER -->
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<tr><td><td>
<center>
<a href="../../"><img src="../../dist/spaceglenda100.png" alt="Space Glenda" border=1></a>
</center>
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<!-- TRAILER -->
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