Self-reproducing programs
The idea of self-reproducing programs dates back to the 1960s. My favorite statement of the problem is the one Ken Thompson gave in his 1983 Turing Award address:
In college, before video games, we would amuse ourselves by posing programming exercises. One of the favorites was to write the shortest self-reproducing program. Since this is an exercise divorced from reality, the usual vehicle was FORTRAN. Actually, FORTRAN was the language of choice for the same reason that three-legged races are popular.
More precisely stated, the problem is to write a source program that, when compiled and executed, will produce as output an exact copy of its source. If you have never done this, I urge you to try it on your own. The discovery of how to do it is a revelation that far surpasses any benefit obtained by being told how to do it. The part about “shortest” was just an incentive to demonstrate skill and determine a winner.
Spoiler alert! I agree: if you have never done this, I urge you to try it on your own. The internet makes it so easy to look things up that it’s refreshing to discover something yourself once in a while. Go ahead and spend a few days figuring out. This blog will still be here when you get back. (If you don’t mind the spoilers, the entire Turing award address is worth reading.)
code
/* Go quine */
package main
import "fmt"
func main() {
fmt.Printf("%s%c%s%c\n", q, 0x60, q, 0x60)
}
var q = `/* Go quine */
package main
import "fmt"
func main() {
fmt.Printf("%s%c%s%c\n", q, 0x60, q, 0x60)
}
var q = `
