.github/workflows | ||
src | ||
.gitignore | ||
CMakeLists.txt | ||
LICENSE | ||
main.cpp | ||
man.md | ||
README.md |
dc ![](https://github.com/ceticamarco/dc/actions/workflows/dc.yml/badge.svg)
dc is an advanced, scientific and programmable RPN desktop calculator with macro support (re)written in C++. By default, dc supports a wide range of arithmetical, trigonometrical and numeric functions. Its capabilities can be further extended by writing user-defined programs using the embedded, turing-complete, macro system.
dc reads from the standard input, but it can also work with text files using the -f
flag. Futhermore, you can decide to evaluate an expression
without opening the REPL by using the -e
flag.
Operands are pushed onto the stack following the LIFO policy; operators, on the other hand, pop one or more values from the stack and push back the result. By default dc is very quiet, in order to inquiry the stack you need to use one of the supported options(see below).
dc
can be invoked with the following command line options:
RPN desktop calculator with macro support. Usage:
-e, --expression <EXPRESSION> | Evaluate an expression
-f, --file <FILE> | Evaluate a file
-h, --help | Show this helper
-V, --version | Show version
Some of the supported features are:
- Basic arithmetical operations(
+
,-
,*
,/
,^
,%
); - Scientific notation support(
5e3
->5000
); - Trigonometrical functions(
sin
,cos
,tan
,asin
,acos
,atan
); - Base conversion(binary:
pb
, octal:po
, hexadecimal:px
); - Factorial and constants(
!
,pi
,e
); - Stack operations:
- Print top element(
p
,P
); - Clear the stack(
c
); - Remove top element(
R
); - Swap order of top two elements(
r
); - Duplicate top element(
d
); - Dump the whole stack(
f
);
- Print top element(
- Parameters:
- Set precision(
k
); - Set input and output radix(
i
ando
);
- Set precision(
- Registers:
- Store top element of the stack on register
X
(sX
orSX
); - Load content of register
X
on top of the stack(lX
orLX
);
- Store top element of the stack on register
- Arrays:
- Store second-to-top of main stack into array
X
indexed by top-of-stack(:X
); - Pop top-of-stack and use it as an index for array
X
(;X
);
- Store second-to-top of main stack into array
- Macros:
- Define a new macro inside square brackets(
[ ]
); - Executing a macro from the stack(
x
); - Evaluate a macro by comparing top-of-head and second-of-head elements(
>X
,<X
,>=X
,<=X
,!=
whereX
is a register).
- Define a new macro inside square brackets(
And much more. You can find the complete manual here.
Installation
dc
is written in C++20 without using any additional dependency. In order to build it, install a recent version of CMake and issue
the following command:
$> mkdir build && cd build
$> cmake .. && make
A new statically-compiled binary called dc
will be created in your local folder.
To generate a man page from the man.md
document, use the following command(note: needs pandoc):
$> pandoc man.md -s -t man > dc.1
Usage
dc can be used in three different ways:
- From the interactive REPL(run it without any argument);
- By evaluating an inline expression, i.e.
$> dc -e "5 5 + p"
- By evaluating a text file, i.e.
$> cat foo 2 4 - # Evaluate 2 - 4 2 ^ # Evaluate x^2 p # Print the result(4) $> dc -f foo 4
Below there are more examples.
- Evaluate
\frac{-5 + \sqrt(25 - 16)}{2}
-5 25 16 - v + 2 / p
where v
is the square root function
- Evaluate
\frac{.5 + .9}{3^4}
.5 .9 + 3 4 ^ / p
- Evaluate
10 + 5
inline(i.e. without opening the REPL):
$> dc -e "10 5 +"
- Evaluate an expression from a file:
$> cat foo
5 5 +
2 d * v
f
$> dc -f ./foo
- Evaluate
\sin(2\pi) + \cos(2\pi)
2 pi * sin 2 pi * cos + p
- Swap top two elements using registers(you can also use the
r
command):
5 4 p # Load some values on the stack(output: 4)
sA sB # Pop values and store them into the registers 'A' and 'B'
lA lB # Push 'A' and 'B' content onto the stack
p # Print top element(output: 5)
- Print out numbers from 1 through user-defined upper bound:
[ p 1 + d lN >L ] sL # Print numbers from 1 through 'N'
[ Enter limit: ] P # Ask user for limit 'N'
? 1 + sN # Read from stdin
c 1 lL x # Clear the stack, add lower bound, load and execute macro
- Sum the first 36 natural numbers(😈), i.e.,
\sum_{i=1}^{37} i = 666
$> dc -e "36 [ d 1 - d 1 <F + ] d sF x p"
- Print the first 20 values of
n!
:
[ la 1 + d sa * p la 20 >y ] sy
0 sa 1
ly x
- Compute the factorial of a given number:
[ ln 1 - sn ln la * sa ln 1 !=f ] sf
[ Enter value: ] P ? sn
ln sa
lf x
la p
- Compute the sum
8AB6F + B783E
in base 16. Print the result in base 10 and in base 2:
16 i
8AB6F B783E +
[ Result in base 10: ] P R p
[ Result in base 2: ] P R pb
- Compute the Greatest Common Divisor(GCD) between two user-defined numbers
A
andB
:
[ Enter A: ] P R ?
[ Enter B: ] P R ?
[ d Sa r La % d 0 <a ] d sa x +
[ GCD(A,B)= ] P R p
- Compute the Least Common Multiple(LCM) between two user-defined numbers
A
andB
:
[ Enter A: ] P R ? d sA
[ Enter B: ] P R ? d SA
[ d Sa r La % d 0 <a ] d sa x +
LA lA * r /
[ LCM(A,B)= ] P R p
- Find the roots of a quadratic equation of the form:
ax^2 + bx + c = 0
with $$a,b,c \in \mathbb{R}, a \neq 0$$
using the formula
x_{1,2} = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}
#!/usr/local/bin/dc -f
# GIVEN A QUADRATIC EQUATION OF THE FORM
# AX^2 + BX + C = 0
# COMPUTE ITS REAL ROOTS
# THIS PROGRAM DOES NOT WORK WITH CMPLX NUMBERS
# DEVELOPED BY MARCO CETICA 2023
#
3 k
[ Enter A: ] P ? sA
[ Enter B: ] P ? sB
[ Enter C: ] P ? sC
lB 2 ^ 4 lA lC * * - v sD
lB -1 * lD - lA # NEGATIVE DELTA
2 * / sS # FIRST SOLUTION
lB -1 * lD + lA # POSITIVE DELTA
2 * / SS # SECOND SOLUTION
[ X1: ] P R lS p
[ X2: ] P R LS lS p