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

int main(int argc, char *argv[]){

FILE *in;

int izbor;
int c;
int asc=0;
char naziv[20];
char unos[100];

char *sifra;


printf("1. Unos\n");
printf("2. Citanje\n");

printf("Unesi izbor: ");
scanf("%d",&izbor);

switch(izbor){
case 1:
    in=fopen(argv[1],"wb");
    scanf("%s",unos);
    sifra=(char*)calloc(strlen(unos)+1,1);

    for(int i=0;i<strlen(unos);i++){
        if(unos[i]>='A' && unos[i]<='Z'){
                asc=unos[i]+3;
                if(asc>=90)asc=65+(asc-90);
                sifra[i]=(char)(asc);}

        if(unos[i]>='a' && unos[i]<='z'){
            asc=unos[i]+3;
            if(asc>=122)asc=97+(asc-122);
                sifra[i]=(char)(asc);}
    }
    printf("%s",sifra);
fwrite(sifra,1,sizeof(sifra),in);

break;
case 2:

    scanf("%s",naziv);
    if(strcmp(naziv,"#")==0){
        in=fopen(argv[1],"rb");
    }
    else in=fopen(naziv,"rb");
    while((c=getc(in))!=EOF){ //this line
        printf("%c",c);
    }

    break;
default:
    printf("NEUSPJESNO!");


}
fclose(in);
return 0;}