From: utzoo!decvax!harpo!eagle!mhuxt!mhuxi!mhuxj!mhuxv!burl!sb1!ll1!ihldt!ixn5c!iwsl3!jpk
Newsgroups: net.jokes
Title: rot 13 source
Article-I.D.: iwsl3.121
Posted: Tue Jan 11 13:27:26 1983
Received: Thu Jan 13 06:57:48 1983
Reply-To: jpk@iwsl3.UUCP (J Kehn)

The source for a rot X program is :

/* rotation program */
#include 
main(argc,argv)
int argc;
char **argv;
{

	int r,c,p;
	char out;

	r = atoi(argv[1]);
	while((c=getchar()) != EOF) {
		out = c;
		if(out>='A' && out<='Z') {
			p = out-'A';
			p = p+r;
			if(p>25) p = p -26;
			out='A' + p;
			putchar(out);
		}
		else
		if(out>='a' && out<='z') {
			p = out-'a';
			p = p+r;
			if(p>25) p = p -26;
			out='a' + p;
			putchar(out);
		}
		else
			putchar(out);
	}
}