Calculon is a command line calculator supporting typical operations on integers, doubles, and strings. The operations it supports are addition, subtraction, multiplication, division, integer division, modulos, exponents, and string concatenation. Variables may be used to store intermediate results.
Calculon was created as part of data structures and algorithms course at The University of Alabama.
Simply running make will compile the executable, "calculon".
Calculon takes a text file as input; the file may be provided through standard input or by supplying the name of the file as a command line argument. As such, the following ways of invoking Calculon from a POSIX shell are equivalent:
./calculon in.txt
cat in.txt | calculon
Calculon will output the value of the last expression in the file. The input has fairly strict formatting requirements; expressions must be terminated with a semicolon, and individual elements must be separated by whitespace.
Variables can be declared using this syntax: "var name = [expression]". For
example, running echo 'var a = 1 ; 5 * ( a + a ) ; ' | calculon outputs 10.
Calculon makes a distinction between integers and floating point numbers. As
such, the expression 9 / 4 will perform integer division and result in a value
of 2. Integer promotion occurs as expected; 9.0 / 9 / 2 results in 0.5 and
9.0 / ( 9 / 2 ) results in 2.25.
When run with the "-d" flag, Calculon will print the last expression to standard
output in postfix notation instead of evaluating it. For example, echo '1 * 2 - 3 / 4 ; ' | ./calculon -d prints 1 2 * 3 4 / -