simple progran to maintain inventory

[new2C]

Hi,

Given the following can anyone complete it so that I can add books to an inventory. I am complete beginner and lost on where to go with it. From there I need to develop it to find, and modify books in the inventory. If I can just get the add part going I think I can do the rest. I am programming in C and using Unix to compile.

Thanks for any help!

#include <stdio.h>


FILE* datafile = fopen(&quot;books.dat&quot;, &quot;w&quot;
if (datafile == NULL) {
/* ... could not create file ... */
}


typedef struct Book_ {
char title[40];
char author[40];
char publisher[50];
float cost;
int pages;
} Book;

 

[aphrodita]

I do not see what could be the problem here. You need to create a variable of type Book and initialize its fields, then append to the file contents.

Book NewBook;
NewBook.title = &quot;The Wheel of Time / Lord of Chaos&quot;;
NewBook.author = &quot;Robert Jordan&quot;;
NewBook.publisher = &quot;Tom Doherty Associates, Inc&quot;;
NewBook.cost = 19.95;
NewBook.pages = 716;

Then you write NewBook to the file. Best Regards,

aphrodita@mail.krovatka.ru {uiuc rules}

http://www.hellforge.org

 

[rbobbitt]

Except for you can't initalize the members of Book like that since they're arrays. You'll need strcpy().

/* Incomplete, untested and some error checking omitted */

#include <stdlib.h>
#include <string.h>

typedef struct Book_ {
char title[40];
char author[40];
char publisher[50];
float cost;
int pages;
} Book;

/* create a book */

Book *
createBook(const char *title,
const char *author,
const char *publisher,
float cost,
int pages)
{
Book *book=malloc(sizeof *book);
if (book!=NULL) {
strcpy(book->title,title);
strcpy(book->author,author);
strcpy(book->publisher,publisher);
book->cost=cost;
book->pages=pages;
}
return book;
}

/* destroy a book */
void
destroyBook(Book *book)
{
free(book);
}
/* write a book to a file */
int
writeBook(Book *book,const char *fname)
{
/* ... */
}
Book *newBook=createBook(&quot;Tons and Tons of Bees&quot;,
&quot;Spatula&quot;,
&quot;Spartacus&quot;,
9.95,
20000);

if (newBook!=NULL) {
if (writeBook(newBook,&quot;myfile.txt&quot!=0) {
/* error */
}
destroyBook(newBook);
}

If you need more help, post the code you're having trouble with.

Russ
bobbitts@hotmail.com

http://home.earthlink.net/~bobbitts