ROT13-stringovi

#include <stdio.h>
#include <stdlib.h>

int AdoN (char c) {
    if (tolower(c)>='a' && tolower(c)<='n') return 1;
    return 0;
}
int MdoZ ( char c) {
    if (tolower(c)>='m' && tolower(c)<='z') return 1;
    return 0;
}

void unos (char *s) {
    char c;
    while (c=getchar(), c!='\n')
        *(s++)=c;
    *s='\0';
}

int length(char *string)
{
    int len = 0;
    while(*(string++) != '\0') len++;

    return len;
}


void ROT13 (char *string) {
    int i, duzina=length(string);
    for (i=0; i<duzina; i++)
 {   if (AdoN(string[i])) string[i]+=13;
 else if (MdoZ(string[i])) string[i]-=13;

 }}




int main () {
    char rec[100];
    unos(rec);
    ROT13(rec);
    printf("%s", rec);
    return 0;
}