void pridaj(KNIZNICA **p_zac, int c1){
 KNIZNICA *pom,*p_pred, *novy;
 char s[102];
 int i=0;
 for(pom=(*p_zac);pom->p_dalsi!=NULL;pom=pom->p_dalsi){
    i++;
    if (c1==1){
        novy=(KNIZNICA*) malloc(sizeof(KNIZNICA));
        novy->p_dalsi=*p_zac;
        while ((fgets(s,102,stdin)) != NULL){
        fgets(novy->signatura, 12, stdin);
        fgets(novy->isbn, 15, stdin);
        fgets(novy->nazov, 102, stdin);
        fgets(novy->autor, 102, stdin);
        scanf("%d\n", &novy->datum);
        scanf("%d\n", &novy->preukaz);
        break;}
        break;
    }
    if (i==c1)
        break;
    p_pred=pom;
 }

    if (c1!=1){
    p_pred->p_dalsi=(KNIZNICA*) malloc(sizeof(KNIZNICA));

   if (pom!=NULL)
    while ((fgets(s,102,stdin)) != NULL){
        fgets((p_pred->p_dalsi)->signatura, 12, stdin);
        fgets((p_pred->p_dalsi)->isbn, 15, stdin);
        fgets((p_pred->p_dalsi)->nazov, 102, stdin);
        fgets((p_pred->p_dalsi)->autor, 102, stdin);
        scanf("%d\n", &(p_pred->p_dalsi)->datum);
        scanf("%d\n", &(p_pred->p_dalsi)->preukaz);

      p_pred->p_dalsi->p_dalsi=pom;
      break;
    }


    }

}