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DC (I)                       1/15/73                       DC (I)

NAME            dc -- desk calculator

SYNOPSIS        dc [file]

DESCRIPTION     dc is an arbitrary precision integer arithmetic

package.  The overall structure of dc is a stack-

ing (reverse Polish) calculator.  The following

constructions are recognized by the calculator:

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 under-

score (_) to input a negative number.

+ - * / % ^

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.

sx

The top of the stack is popped and stored into

a register named x, where x may be any charac-

ter.

lx

The value in register x is pushed on the

stack.  The register x is not altered.  All

d

The top value on the stack is pushed on the

stack.  Thus the top value is duplicated.

p

The top value on the stack is printed.  The

top value remains unchanged.

f

All values on the stack and in registers are

printed.

q

exits the program. If executing a string, the

nesting level is popped by two.

x

treats the top element of the stack as a char-

acter string and executes it as a string of dc

commands.

[...]

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.

!

interprets the rest of the line as a UNIX com-

mand.

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.

o

the top value on the stack is popped and used

as the number radix for further output.

z

the stack level is pushed onto the stack.

?

a line of input is taken from the input source

(usually the console) and executed.

new-line

ignored except as the name of a register or to

end the response to a ?.

space

ignored except as the name of a register or to

terminate a number.

If a file name is given, input is taken from that

file until end-of-file, then input is taken from

the console.

An example to calculate the monthly, weekly and

hourly rates for a \$10,000/year salary.

10000

100*    (now in cents)

dsa     (non-destructive store)

12/     (pennies per month)

la52/   (pennies per week)

d10*    (deci-pennies per week)

375/    (pennies per hour)

f       (print all results)

512

19230

83333

"a"  1000000

An example which prints the first ten values of n! is

[la1+dsa*pla10>x]sx

0sa1

lxx

FILES           --

DIAGNOSTICS     (x) ? for unrecognized character x.

(x) ? for not enough elements on the stack to do

what was asked by command x.

"Out of space" when the free list is exhausted

(too many digits).

"Out of headers" for too many numbers being kept

around.

"Out of pushdown" for too many items on the

stack.

"Nesting Depth" for too many levels of nested ex-

ecution.

BUGS            --

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