我能够将数据输入到程序中，并使用一些printf语句来查看数据是否被正确写入。当我要打印一个记录或所有记录时，该程序将强制退出并退出（dispAll）或变得乱七八糟，并且即使我基于该键前往同一位置，也找不到找到的记录。
我添加了很多打印语句来查看记录中的值，但是混合结果决定了丢失数据的位置。
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
struct Record
{
int available;
int itemID;
char itemName [16];
char itemDescription [31];
double itemUnitPrice;
int itemOnHand;
double value;
int key;
};
// function prototypes
void displayMenu ();
int getChoice ();
void processChoice (int pChoice);
void addRecord();
void modRecord ();
void dispOneRecord ();
void dispAllRecords ();
void dispItem (struct Record inventory);
int main (void)
{ //opens the function main
// Local Declarations
int pChoice;
struct Record inventory;
int i;
FILE* fp;
int ava = 0;
// Statements
// creates a file to be used by the program
fp = fopen ("invent.txt", "wb+");
for (i = 0; i < 23; i++)
{
fseek(fp, i * sizeof(struct Record), SEEK_SET);
fwrite(&ava, sizeof(int), 1, fp);
}
fclose (fp);
do
{ // begins do loop
displayMenu();
pChoice = getChoice();
processChoice (pChoice);
}
while (pChoice != 5); // ends do loop
return(0);
} // closes main
void displayMenu ()
{
printf("\n ***********************************************************\n");
printf("\n Inventory Management System \n");
printf("\n Select the number for the action you would like to conduct.\n");
printf("\n 1 - Add Inventory Records to File");
printf("\n 2 - Modify Data in an Inventory Record");
printf("\n 3 - Display One Item and Value");
printf("\n 4 - Report all Inventory and the Total Value");
printf("\n 5 - Exit the Program\n\n");
printf("\n ***********************************************************\n");
return;
}
int getChoice ()
{
// local variables
int pChoice;
// prompts the user for their choice
printf("\nPlease enter your choice: ");
scanf("%d", &pChoice);
return(pChoice);
}
void processChoice (int pChoice)
{
switch (pChoice)
{
case 1:
addRecord();
break;
case 2:
modRecord();
break;
case 3:
dispOneRecord();
break;
case 4:
dispAllRecords();
break;
}
return;
}
void addRecord()
{
//Local Variables
FILE* fp;
struct Record inventory;
printf("\nPlease enter the Item Identification Number: ");
scanf("%d", &inventory.itemID);
printf("\nPlease enter the Item Name (Limit of 15 Characters): ");
scanf("%s", inventory.itemName);
printf("\nPlease enter the Item Description (Limit of 30 Characters): ");
scanf("%s", inventory.itemDescription);
printf("\nPlease enter the Item Unit Price: $");
scanf("%lf", &inventory.itemUnitPrice);
printf("\nPlease enter the number of Items on Hand: ");
scanf ("%d", &inventory.itemOnHand);
inventory.value = inventory.itemUnitPrice * inventory.itemOnHand;
fp = fopen("invent.txt", "rb+");
inventory.key = inventory.itemID % 23;
printf ("\n%d", inventory.key);
fseek(fp, inventory.key * sizeof(struct Record), SEEK_SET);
fread (&inventory.available, sizeof(int), 1, fp);
printf ("\n%d", inventory.available);
if (inventory.available == 0)
{
fseek(fp, inventory.key * sizeof(struct Record), SEEK_SET);
inventory.available = 1;
fwrite(&inventory, sizeof(struct Record), sizeof(struct Record), fp);
printf ("\nI wrote the record. %d key=%d, name=%s", inventory.available, inventory.key, inventory.itemName);
fclose (fp);
}
else
while (inventory.available == 1)
{
inventory.key = inventory.key + 1;
fread (&inventory.available, sizeof(int), 1, fp);
if (inventory.available == 0)
{
fseek(fp, inventory.key * sizeof(struct Record), SEEK_SET);
inventory.available = 1;
fwrite (&inventory, sizeof(struct Record), sizeof(struct Record), fp);
printf ("\nResolved collision and wrote the file.");
fclose (fp);
} // end if
} // end while
return;
}
void modRecord ()
{
//local variables
FILE* fp;
struct Record inventory;
printf ("\nPlease enter the Item ID: ");
scanf ("%d", &inventory.itemID);
fp = fopen("invent.txt", "rb+");
inventory.key = inventory.itemID % 23;
fseek(fp, inventory.key * sizeof(struct Record), SEEK_SET);
fread (&inventory.available, sizeof(int), 1, fp);
if (inventory.available == 0)
printf ("\nNo Record Found.");
else if (inventory.available == 1)
{
fseek(fp, inventory.key * sizeof(struct Record), SEEK_SET);
printf("\nPlease enter the Item Name (Limit of 15 Characters): ");
scanf("%s", inventory.itemName);
printf("\nPlease enter the Item Description (Limit of 30 Characters): ");
scanf("%s", inventory.itemDescription);
printf("\nPlease enter the Item Unit Price: $");
scanf("%lf", &inventory.itemUnitPrice);
printf("\nPlease enter the number of Items on Hand: ");
scanf ("%d", &inventory.itemOnHand);
inventory.value = inventory.itemUnitPrice * inventory.itemOnHand;
fp = fopen("invent.txt", "rb+");
fseek(fp, inventory.key * sizeof(struct Record), SEEK_SET);
fread (&inventory.available, sizeof(int), 1, fp);
fwrite(&inventory, sizeof(struct Record), sizeof(struct Record), fp);
fclose (fp);
} // end if
return;
}
void dispOneRecord ()
{
// local variables
FILE* fp;
struct Record inventory;
printf ("\nPlease enter the Item ID: ");
scanf ("%d", &inventory.itemID);
fp = fopen("invent.txt", "rb+");
inventory.key = inventory.itemID % 23;
printf ("\n%d", inventory.key);
fseek(fp, inventory.key * sizeof(struct Record), SEEK_SET);
fread (&inventory, sizeof(int), 1, fp);
printf ("\n%d, %s", inventory.available, inventory.itemName);
if (inventory.available == 0)
printf ("\nNo Record Found.");
else if (inventory.available == 1)
{
fseek(fp, inventory.key * sizeof(struct Record), SEEK_SET);
fread (&inventory, sizeof(struct Record), sizeof(struct Record), fp);
printf ("\nI have found the record.");
printf ("\nItem ID: %-d\n", inventory.itemID);
printf ("\nItem Name: %-s\n", inventory.itemName);
printf ("\nItem Description: %-s\n", inventory.itemDescription);
printf ("\nItem Unit Price: $%-0.2lf\n", inventory.itemUnitPrice);
printf ("\nNumber of Item on Hand: %-d\n\n\n", inventory.itemOnHand);
printf ("\nTotal Value of Items on Hand: $%-0.2lf\n", inventory.value = inventory.itemUnitPrice * inventory.itemOnHand);
} // end if
return;
}
void dispAllRecords ()
{
// local variables
FILE* fp;
struct Record inventory;
double tValue = 0;
printf("\n ***********************************************************\n");
printf("\n Inventory Management System \n");
printf("\n ***********************************************************\n");
inventory.key = 0;
while (inventory.key < 23)
{
fseek (fp, inventory.key * sizeof(struct Record), SEEK_SET);
fread (&inventory, sizeof(int), 1, fp);
if (inventory.available == 0)
inventory.key = inventory.key + 1;
else
{
fseek(fp, inventory.key * sizeof(struct Record), SEEK_SET);
fread (&inventory, sizeof(struct Record), sizeof(struct Record), fp);
printf ("\nItem ID: %-d\n", inventory.itemID);
printf ("\nItem Name: %-s\n", inventory.itemName);
printf ("\nItem Description: %-s\n", inventory.itemDescription);
printf ("\nItem Unit Price: $%-0.2lf\n", inventory.itemUnitPrice);
printf ("\nNumber of Item on Hand: %-d\n\n\n", inventory.itemOnHand);
printf ("\nTotal Value of Items on Hand: $%-0.2lf\n", inventory.value = inventory.itemUnitPrice * inventory.itemOnHand);
tValue = tValue + inventory.value;
inventory.key = inventory.key + 1;
} // end if
} // end while
printf ("\nThe total value of the inventory is: $%lf", tValue);
return;
}
允许用户将数据输入到随机访问文件中 修改该记录 查找并显示一条记录 查找并显示所有记录并显示库存的总价值