Thread: Help with library system

Originally Posted by Salem

Well apart from the train wreck of using gets(), the next problem I see is your recursive calls to adminact(); every time you finish something.

viewbook() for example should just return; and it is right back in the middle of adminact() where it was called from.

If you want a normal user to call viewbook(), you would want to return to the normal user function as well.

If I won't use adminact() to go back, what can I use?

Originally Posted by Mr.777

Practically, you can't remove from the static arrays, and also you are assigning the title as " ".
So, in viewbook function, don't show the books which have title as " ".
Simple :-)

I didn't quite understand what you were pointing out. XD

OK, let's say we have a menu() function, that shows the options we can choose. We choose addBook(), and add a book. Now, how do we get back to the menu again?

We simply do nothing!
Sample menu code:

Code:

void menu() {
  int choice = 9;
  while(choice != '0') {
    printf("\n\n\n Welcome to the Library Menu\n\n");
    printf("
    1. Add a Book\n\
    2. Delete a Book\n\
    3. Edit a Book Record\n\
    4. Search for a Book\n\
    5. View all Books\n\n");

    printf("Your Choice (0 to Quit) >> ");
    scanf("%c", &choice);
    (void) getchar();
    choice = tolower(choice); //include ctype.h for tolower()

    switch(choice) {
      case 1: addBook(); break;
      case 2: etc.
      //etc.
    } //end of switch
  } //end of while
} //end of menu()

Without doing anything, after we call "addBook()", the program will return and execute the next code, which is "break". Then the menu will be printed up again.

No recalling the menu() function is necessary. (And if you do it, it will break your program before long).

Now say we had a main menu() and an adminMenu(), and we're at the main menu(). So we choose adminMenu() to do some admin work, then we would loop back (first), to the adminMenu() function, just by returning. If we return again, we're now back at the main menu() function.

That's how the call stack works - like a plate stack in your kitchen. You put plates on the stack, and then remove them, always by taking off the top plate, not just ANY plate. Every time you add a plate to the stack of plates, it's a PUSH, and every time you remove a plate, it's a POP. Every time you call a function, it's a PUSH of the return address, onto the stack. Every time you return from a function, it's a POP off of the stack.

And now it's time to have some lunch!

Originally Posted by Adak

choice = tolower(choice)
[/code]

What does the tolower() function do?

Originally Posted by hexarthrius

What does the tolower() function do?

Look it up in your library documentation...

Ahh... Right. XD