DC(C) UNIX System V
Name
dc - invokes an arbitrary precision calculator
Syntax
dc [ file ]
Description
dc is an arbitrary precision arithmetic package. Ordinarily
it operates on decimal integers, but you 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 0-9. 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 and the result 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 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 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.
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 nonnegative 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.
? A line of input is taken from the input source
(usually the terminal) and executed.
; : Used by bc for array operations.
Example
This example prints the first ten values of n!:
[la1+dsa*pla10>y]sy
0sa1
lyx
See Also
bc(C)
Diagnostics
x is unimplemented The octal number x corresponds to a
character that is not implemented
as a command
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
Notes
bc is a preprocessor for dc, providing infix notation and a
C-like syntax which implements functions and reasonable
control structures for programs. For interactive use, bc is
preferred to dc .
(printed 2/15/90) DC(C)