Programs that write themselves.
A quine is a program that, when run, produces its own source code as its output.
It sounds trivial until you realise that you need to print the code that actually does the printing. (Note that simply reading the source file itself and printing it is considered cheating. Also, the quine program should not need to accept any input.)
Writing a quine requires that you be aware of how the language you’re working in treats its strings, and, in particular, the quotes (ie. ' and ") around said strings.
Most quines would typically involve some form of printf. The following OCaml program is an example of such a quine:
let q=char_of_int 34 and x="let q=char_of_int 34 and x=%c%s%cin Printf.printf%c%s%cq x q q x q"in Printf.printf"let q=char_of_int 34 and x=%c%s%cin Printf.printf%c%s%cq x q q x q"q x q q x qThe quines found in this repository correspond to the handful of programming languages that I have used a fair bit, and have moderate proficiency with. Note that each program is supposed to be the shortest quine for the language that I can think of, and is not meant to be readable.
You will first need to install the compiler or interpreter for each language.
Then, run the test.sh shell script in the root of this repository:
$ bash test.sh
- 0.1.0
- Initial release