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

int main ()
{
FILE * fp;
 struct dst
  {
  char     name[30];
  char     vorname[30];
  char     telnr[20];
  struct dst *ptr;
  };
 struct dst dat;
 printf("\n name:");
 scanf("%s", dat.name);
 printf("\n vormane:");
 scanf("%s", dat.vorname);
 printf("\n tel.:");
 scanf("%s", dat.telnr);

 fp = fopen ("test.datei","ab");
 if (fp == NULL)
  {
  fprintf(stderr,"\n Kei Öffnen\n");
  exit(3);
  }
 fwrite(&dat, sizeof(dat),1,fp);
 return(fclose(fp));
}