#include #include char rot13c(char c) { char u[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; char l[] = "abcdefghijklmnopqrstuvwxyz"; char *p; if ((p = strchr(u, c)) != NULL) return u[((p-u) + 13) % 26]; else if ((p = strchr(l, c)) != NULL) return l[((p-l) + 13) % 26]; else return c; } void main(void) { int c; while ((c = getchar()) != EOF) putchar(rot13c(c)); }