dc(1) DG/UX 4.30 dc(1)
NAME
dc - desk calculator
SYNOPSIS
dc [ file ]
DESCRIPTION
Dc 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. (See bc(1), a preprocessor for dc that
provides infix notation and a C-like syntax that implements
functions. Bc also provides reasonable control structures
for programs.) 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 0-9. 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 (*), or divided (/). The
percent sign (%) shows the remainder when the two
values are divided and the caret (^) shows the result
when one of the two numbers is used as an exponent of
the other. 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 at
zero. 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.
Licensed material--property of copyright holder(s) Page 1
dc(1) DG/UX 4.30 dc(1)
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 dc commands.
X 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. Register x is evaluated 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 DG/UX system
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. 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, division, 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.
Licensed material--property of copyright holder(s) Page 2
dc(1) DG/UX 4.30 dc(1)
? A line of input is taken from the input source
(usually the terminal) and executed.
; : Used by bc for array operations.
EXAMPLES
$ cat dc.infile1
10sa2sb
lad+p
lalb/p
q
$ dc dc.infile1
20
5
$
In this example, the dc command uses dc.infile1 for its
input. The first line of dc.infile1 causes the a and b
registers to be loaded (using "l" for load) with the values
10 and 2, respectively. The next 2 lines use the a and b
register values (using "l" for load again) to perform some
arithmetic. The second line pushes the a register on the
stack, duplicates it and then adds the two numbers together.
The third line pushes the b register and the a register on
the stack and then divides b by a. In both cases the result
is pushed on the stack, and the p causes the result to be
printed to the output file. The 20 is the result of 10+10
and the 5 is the result of 10/2.
$ cat dc.infile2
[3 5 * p]
x
$ dc dc.infile2
15
<Ctrl-D>
$
In this example, dc.infile2 is used for the input for dc.
The first line of the input pushes the strings of commands
onto the stack. The x command treats the top of the stack
as a string of commands and executes them. The p in the
string of commands causes the result (15) to be written as
output. You press <Ctrl-D> to end execution.
$ cat dc.infile3
[6 4 + p] sa
5
Licensed material--property of copyright holder(s) Page 3
dc(1) DG/UX 4.30 dc(1)
5
=a
q
$ dc dc.infile3
10
$
In this example, dc uses dc.infile3 for its input. The
first line of the input causes register a to be loaded with
the given string of commands ([6 4 + p]). The next two
lines cause 2 5s to be pushed on the stack. The =a command
then checks the top 2 values on the stack to see if they are
equal. Since they are, the commands in the a register are
executed. The result (10) is written as output.
SEE ALSO
bc(1).
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.
Licensed material--property of copyright holder(s) Page 4