#define SIZE_OF_BUF 50
#include <stdio.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/time.h>
void printLen(FILE *fin, char * buf, long int len, long int offset)
{
    fseek(fin, offset, SEEK_SET);
    long int bufend = 0;
    long int sum = 0;
    int i;
    while (SIZE_OF_BUF + sum < len)
    {
        bufend = fread(buf, sizeof(char), SIZE_OF_BUF, fin);
        for(i = 0; i<bufend; i++)
            printf("%c", buf[i]);
        sum+=bufend;

    }
    fread(buf, sizeof(char), len - sum, fin);
    for(i = 0; i < len - sum; i++)
        printf("%c", buf[i]);
    printf("\n");
}
int main()
{
    FILE *fin = fopen("lab5text", "r");

    if (fin == NULL)
    {
        perror("Can not open file");
        return 0;
    }

    char buf[SIZE_OF_BUF] = {0};
    long int posofnextl[100] = {0};
    int numofnextl = 0;
    long int curpos = 0;

    size_t bufend;
    while ((bufend = fread(&buf, sizeof(char), SIZE_OF_BUF, fin)) != 0)
    {
        int i = 0;
        for (; i < bufend; i++)
        {
            if ((buf[i] == '\n'))
            {
                posofnextl[numofnextl] = curpos + i;
                numofnextl++;
            }
        }

        if((bufend < SIZE_OF_BUF) && (buf[bufend - 1] != '\n'))
        {
            posofnextl[numofnextl] = curpos + i;
            numofnextl++;
        }
        curpos+=bufend;
    }

    if (numofnextl == 0)
    {
        printf("File is empty \n");
        return 0;
    }

    int i = 0;
    long int lenghts[100] = {0};
    lenghts[0] = posofnextl[0];
    for (i = 1; i < numofnextl; i++)
    {
        lenghts[i] = posofnextl[i] - posofnextl[i-1] - 1;
    }

    long int offsets[100] = {0};
    offsets[0] = 0;
    for(i = 1; i < numofnextl; i++)
    {
        offsets[i] = offsets[i-1] + lenghts[i-1] + 1;
    }

    int numberofstr = 0;

    fd_set input;
    int res;
    struct timeval timeout;
    FD_ZERO(&input);
    FD_SET(0, &input);
    timeout.tv_sec = 5;
    timeout.tv_usec = 0;

    res = select(1, &input, NULL, NULL, &timeout);

    if (res == 0) {
        printf("Не успел\n");
        for(i = 0; i < numofnextl; i++)
        {
            printLen(fin, buf, lenghts[i], offsets[i]);
        }
        return 0;
    }
    else
    {
        //успел
    }

    while (scanf("%d", &numberofstr))
    {
        if (numberofstr == 0)
            break;
        if((numberofstr<=numofnextl) && (numberofstr >0))
        {
            printLen(fin, buf, lenghts[numberofstr-1], offsets[numberofstr-1]);
        }
        else
        {
            printf("Wrong number of str\n");
        }
    }


    fclose(fin);
    return 0;
}