dc(1) manual page
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dc - desk calculator
dc [ filename ]
SUNWesu
dc is an arbitrary precision arithmetic package. 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 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.
bc is a preprocessor for dc that provides infix notation and a C-like syntax
that implements functions. bc also provides reasonable control structures
for programs. See bc(1)
.
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.
- Q
- Exits the program. 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
.Ix 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 shell 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.
- K
- Pushes the current scale factor on the top of the stack.
- 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.
- Y
- Displays dc debugging information.
- ; :
- are used by bc(1)
for array operations.
This example prints
the first ten values of n!:
[la1+dsa*pla10>y]sy
0sa1
lyx
bc(1)
- x is unimplemented
- x is an octal number.
- out of
space
- The free list is exhausted (too many digits).
- out of stack space
- Too
many pushes onto the stack (stack overflow).
- empty stack
- Too many pops from
the stack (stack underflow).
- nesting depth
- Too many levels of nested execution.
- divide by 0
- Division by zero.
- sqrt of neg number
- Square root of a negative
number is not defined (no imaginary numbers).
- exp not an integer
- dc only
processes integer exponentiation.
- exp too big
- The largest exponent allowed
is 999.
- input base is too large
- The input base x: 2<= x <= 16.
- input base is
too small
- The input base x: 2<= x <= 16.
- output base is too large
- The output
base must be no larger than BC_BASE_MAX
.
- invalid scale factor
- Scale factor
cannot be less than 1.
- scale factor is too large
- A scale factor cannot be
larger than BC_SCALE_MAX
.
- symbol table overflow
- Too many variables have
been specified.
- invalid index
- Index cannot be less than 1.
- index is too large
- An index cannot be larger than BC_DIM_MAX
.
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