#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <io.h>

void fgv();
void fgv1();
void fgv2();
void fgv3();

int main()
{
    fgv();
    fgv1();
    fgv2();
    fgv3();

    return 0;
}

void fgv()
{
    int hnd,c;

    hnd=open("adat.txt",O_RDONLY);

    while(1)
    {
        c=read(hnd,&c,sizeof(c));
        if(c==-1) return 1;
        else return 0;
        printf("%c",c);
    }
    close(hnd);
}

void fgv1()
{
    int hnd, r;
    hnd=open("adat.txt",O_RDONLY);
    r=tell(hnd);
    printf("meret = %i bajt\n\n",r);
    close(hnd);
}

void fgv2()
{
    int hnd,i=0,j=0,t[100];

    hnd=open("adat.txt",O_CREAT|O_RDWR,S_IREAD|S_IWRITE);
    while(i<100)
    {
        if(j%3==0)
        {
            t[i]=j;
            i++;
        }
        j++;
    }
    for(i=0;i<100;i++)
    {
        write(hnd,&t[i],sizeof(t[i]));
        printf("%i\t",t[i]);
    }
    close(hnd);
}

void fgv3()
{
    int hnd,i=0,r,j=0,t[100];

    hnd=open("adat.txt",O_CREAT|O_RDWR,S_IREAD|S_IWRITE);
    while(i<100)
    {
        if(j%3==0)
        {
            t[i]=j;
            i++;
        }
        j++;
    }

    hnd=open("adat.txt",O_RDONLY);

    while(1)
    {
        r=read(hnd,&t[i],sizeof(t[i]));
        if(r>0) break;
        close(hnd);
    }
}