March, 2008 Modified from the program invent.c by adding a price member
and operations on it, and also adding the ability to search
by part name.

/*********************************************************
 * From C PROGRAMMING: A MODERN APPROACH, by K. N. King  *
 * Copyright (c) 1996 W. W. Norton & Company, Inc.       *
 * All rights reserved.                                  *
 * This program may be freely distributed for class use, *
 * provided that this copyright notice is retained.      *
 *********************************************************/

/* invent.c (Chapter 16, page 341) */
/* Maintains a parts database (array version) */ 

#include <stdio.h>
#include "readline.h"

#define NAME_LEN 25
#define MAX_PARTS 100

struct part {
  int number;
  char name[NAME_LEN+1];
  int on_hand;
  float price;
} inventory[MAX_PARTS];

int num_parts = 0;   /* number of parts currently stored */

int find_part(int number);
void insert(void);
void search(void);
void update(void);
void print(void);
void ChangePrice(void);

/********************************************************** 
 * main: Prompts the user to enter an operation code,     * 
 *       then calls a function to perform the requested   * 
 *       action. Repeats until the user enters the        * 
 *       command 'q'. Prints an error message if the user * 
 *       enters an illegal code.                          * 
 **********************************************************/
main()
{
  char code;

  for (;;) {
    printf("Enter operation code: ");
    scanf(" %c", &code);
    while (getchar() != '\n')   /* skips to end of line */
      ;
    switch (code) {
      case 'i': insert(); 
                break;
      case 's': search();
                break;
      case 'u': update();
                break;
      case 'p': print();
                break;
      case 'c': ChangePrice();
                break;
      case 'q': return 0;
      default:  printf("Illegal code\n");
    }
    printf("\n");
  }
}

/********************************************************** 
 * find_part: Looks up a part number in the inventory     * 
 *            array. Returns the array index if the part  * 
 *            number is found; otherwise, returns -1.     * 
 **********************************************************/
int find_part(int number)
{
  int i;

  for (i = 0; i < num_parts; i++)
    if (inventory[i].number == number)
      return i;
  return -1;
}

int FindPartByName( char *name )
{
  int i;

  for (i = 0; i < num_parts; i++)
    if ( ! strcmp(inventory[i].name, name) )
      return i;
  return -1;
}

/********************************************************** 
 * insert: Prompts the user for information about a new   * 
 *         part and then inserts the part into the        * 
 *         database. Prints an error message and returns  * 
 *         prematurely if the part already exists or the  * 
 *         database is full.                              * 
 **********************************************************/
void insert(void)
{
  int part_number;

  if (num_parts == MAX_PARTS) {
    printf("Database is full; can't add more parts.\n");
    return;
  }

  printf("Enter part number: ");
  scanf("%d", &part_number);
  if (find_part(part_number) >= 0) {
    printf("Part already exists.\n");
    return;
  }

  inventory[num_parts].number = part_number;
  printf("Enter part name: ");
  read_line(inventory[num_parts].name, NAME_LEN);
  printf("Enter quantity on hand: ");
  scanf("%d", &inventory[num_parts].on_hand);

  // ask the user for the price
  printf( "Enter price: " );
  scanf( "%f", &inventory[num_parts].price );

  num_parts++;
}

/********************************************************** 
 * search: Prompts the user to enter a part number, then  * 
 *         looks up the part in the database. If the part * 
 *         exists, prints the name and quantity on hand;  * 
 *         if not, prints an error message.               * 
 **********************************************************/
void searchByPartNumber(void)
{
  int i, number;

  printf("Enter part number: ");
  scanf("%d", &number);
  i = find_part(number);
  if (i >= 0) {
    printf("Part name: %s\n", inventory[i].name);
    printf("Quantity on hand: %d\n", inventory[i].on_hand);
    printf( "Price: %4.2f\n", inventory[i].price );
  } else
    printf("Part not found.\n");
}

void searchByPartName(void)
{
  int i;
  char partName[NAME_LEN+1];

  printf("Enter part name: ");
  read_line( partName, NAME_LEN );
  i = FindPartByName( partName );
  if (i >= 0)
  {
    printf("Part name: %s\n", inventory[i].name);
    printf("Quantity on hand: %d\n", inventory[i].on_hand);
    printf( "Price: %4.2f\n", inventory[i].price );
  } else
    printf("Part not found.\n");
}

void search(void)
{
#if defined(EXTRA)
  int i, number;

  printf("Search by Part Number enter 1 or a Part Name enter 2: ");
  scanf("%d", &number);

  switch( number )
  {
  case 1:
    // Search by Part Number
    searchByPartNumber();
    break;
  case 2:
    searchByPartName();
    break;
  }
#else
	searchByPartNumber();
#endif
}

/********************************************************** 
 * update: Prompts the user to enter a part number.       * 
 *         Prints an error message if the part doesn't    * 
 *         exist; otherwise, prompts the user to enter    * 
 *         change in quantity on hand and updates the     * 
 *         database.                                      * 
 **********************************************************/
void update(void)
{
  int i, number, change;

  printf("Enter part number: ");
  scanf("%d", &number);
  i = find_part(number);
  if (i >= 0) {
    printf("Enter change in quantity on hand: ");
    scanf("%d", &change);
    inventory[i].on_hand += change;
  } else
    printf("Part not found.\n");
}

void ChangePrice()
{
  int i, number;
  float newPrice;

  printf("Enter part number: ");
  scanf("%d", &number);
  i = find_part(number);
  if (i >= 0) {
    printf("Enter new price: ");
    scanf("%f", &newPrice);
    inventory[i].price = newPrice;
  } else
    printf("Part not found.\n");
}

/********************************************************** 
 * print: Prints a listing of all parts in the database,  * 
 *        showing the part number, part name, and         * 
 *        quantity on hand. Parts are printed in the      * 
 *        order in which they were entered into the       * 
 *        database.                                       * 
 **********************************************************/
void print(void)
{
  int i;

  printf("Part Number   Part Name                  "
         "Quantity on Hand   Price\n");
  for (i = 0; i < num_parts; i++)
    printf("%7d       %-25s%11d           %4.2f\n", inventory[i].number,
           inventory[i].name, inventory[i].on_hand, inventory[i].price);
}