books-ptr-wrong.c - Et eksempel på overførsel og tilbageførsel af bøger per refererence - virker ikke.

Lektion 9 - slide 12 : 29 Program 1

/* Incorrect program - see books-ptr.c for a better version */

#include <stdio.h>

struct book {
  char *title, *author, *publisher;
  int publishing_year;
  int university_text_book;
};

typedef struct book book;

book *make_book(char *title, char *author, char *publisher, 
               int year, int text_book){
  static book result;
  result.title = title; result.author = author;
  result.publisher = publisher; result.publishing_year = year;
  result.university_text_book = text_book;
 
  return &result;
}

void prnt_book(book *b){
  char *yes_or_no;

  yes_or_no = (b->university_text_book ? "yes" : "no"); 
  printf("Title: %s\n"
         "Author: %s\n"
         "Publisher: %s\n"
         "Year: %4i\n"
         "University text book: %s\n\n",
         b->title, b->author, b->publisher, 
         b->publishing_year, yes_or_no);
}

int main(void) {

  book *b1, *b2;

  b1 = make_book("C by Disssection", "Kelley & Pohl", 
                 "Addison Wesley", 2001, 1);
  b2 = make_book("Pelle Eroberen", "Martin Andersen Nexoe",
                 "Gyldendal", 1911, 0);

  prnt_book(b1);
  prnt_book(b2);
  
  return 0;
}