dc(1)dc(1)Namedc - desktop calculator
Syntaxdc [file]
Description
The command is an arbitrary precision arithmetic package. Ordinarily
it operates on decimal integers, but you can specify an input base,
output base, and a number of fractional digits to be maintained. The
overall structure of 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
underscore _ 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 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 commands.
X Replaces the number on the top of the stack with its scale fac‐
tor.
[ ... ] 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. When the base (number radix) is re-
set, all subsequent numbers are interpreted in the new base.
For example, if the command is issued twice, first to set the
base to base 2, then to reset it back to base 10, the new base
value must be given in the base originally set (that is, `2 i'
will set the base to base 2, after which `1010 i' will set it
back to base 10).
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, divi‐
sion, and exponentiation. The interaction of scale factor,
input base, and output 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.
; : Used by for array operations.
An example which prints the first ten values of n! is the following:
[la1+dsa*pla10>y]sy
0sa1
lyx
Diagnostics
"x is unimplemented"
x is an octal number.
"stack empty"
Not enough elements on the stack to do what was asked.
"Out of space"
The free list is exhausted (too many digits).
"Out of headers"
Too many numbers being kept around.
"Out of pushdown"
Too many items on the stack.
"Nesting Depth"
Too many levels of nested execution.
See Alsobc(1)dc(1)
