CODEWITHSUNDEEP
csockets
Mike
Mike

Reputation: 7

How to pass up a struct edit[how to store lines]

this output

Andrew Tanenbaum, David Wetherall
    Computer Networks
    Michaell Donahoo, Kenneth Calvert
    TCP/IP Sockets in C
    William,Stallings
    Yale Patt, Sanjay Patel

is the result of this code.




#include <stdio.h>      /* for printf() and fprintf() */
#include <sys/socket.h> /* for socket() and bind() */
#include <arpa/inet.h>  /* for sockaddr_in and inet_ntoa() */
#include <stdlib.h>     /* for atoi() and exit() */
#include <string.h>     /* for memset() */
#include <unistd.h>     /* for close() */
#include "./book.h"
#ifndef fileget_C
#define fileget_C
#endif // fileget_C

 void readlib(Book* Library){
/*char stock[4][125];*/
  FILE *bookfile=fopen("/home/ninja/Sockets/bookstock.txt","r+");


  size_t len=0;
  int num;
  ssize_t read;
  char *stringin;
  char *isbn;
  int *numin;

int n;
  for(n=0; n<4; n=n+1){
  getline(&stringin, &len, bookfile);
  strncpy(Library[n].isbn,stringin,strlen(stringin));
  //printf("%s",Library[n].isbn);
  stringin=NULL;

  getline(&stringin, &len, bookfile);
  strncpy(Library[n].Author,stringin,strlen(stringin));
  //printf("%s",Library[n].Author);
  stringin=NULL;

  getline(&stringin, &len, bookfile);
  strncpy(Library[n].title,stringin,strlen(stringin));
  //printf("%s",Library[n].title);
  stringin=NULL;

  getline(&stringin, &len, bookfile);
  num=atoi(stringin);
  Library[n].edition=num;
  //printf("%d\n",Library[n].edition);
  stringin=NULL;

  getline(&stringin, &len, bookfile);
  Library[n].year=atoi(stringin);
  stringin=NULL;
  //printf("%d\n",Library[n].year);

  getline(&stringin, &len, bookfile);
  strncpy(Library[n].publisher,stringin,strlen(stringin));
  stringin=NULL;


  getline(&stringin, &len, bookfile);
  Library[n].inventory=atoi(stringin);
  stringin=NULL;

  getline(&stringin, &len, bookfile);
  Library[n].available=atoi(stringin);
  //printf("%d\n",Library[n].available);

  }
 // printf("%s",Library[0].title);
  //printf("%s",Library[1].title);
  //printf("%s",Library[2].title);
  //printf("%s\n",Library[3].title);

  printf("%s",Library[0].Author);
  printf("%s",Library[1].Author);
  printf("%s",Library[2].Author);
  printf("%s",Library[3].Author);



}

For some reason, I'm getting extra lines stored or I am not storing to the pointer in an appropriate way. The commented out print lines in the for loop display the right information which includes printing the appropriate author field of the struct.

Upvotes: 0

Views: 76

Answers (1)

Ian
Ian

Reputation: 30813

The problem is with your readlib() and your Library.

Note that the return of the readlib() is not of type Book*, while you return Library which is of type Book[], thus the compiler gives you the warning.

Also, it seems like you are trying to return an array in C. Be very careful. Technically, you could change the return of readlib() like this:

Book* readlib()

But it is highly not recommended. It is better to have array declared outside of the function and the function contains the Book* argument in it:

void readlib(Book* Library, int noOfBook)

Then you declare your

Book Library[4]; //somewhere else

and call the readlib like this:

readlib(Library, 4);

You do not need to to:

return Library;

In the readlib, since it is already declared outside and passed to the readlib

Of course, if you really want to return Book* however, you could prepare proper memory space by using malloc in the function:

Book* readlib(int noOfBook){
    Book *Library = malloc (noOfBook * sizeof(Book));
    //something else
    return Library;
}

But I personally prefer to handle all these outside.

Upvotes: 2

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