I have a C program that is meant to save, edit and delete contacts and save them to a binary file. The struct for the contact is defined as such:
struct Contact {
unsigned long phone_number;
long first_name_posn;
long last_name_posn;
long company_name_posn;
long email_posn;
long next;
}
Each value apart from the phone_number holds the location of the information on the file, and the information is written right after. Now when the program is running, I read all the contacts into a dynamic array. The function below is meant to add an additional contact to the array and stores it. However, when I start with zero contacts and add one, it's fine. But when I attempt to add a second contact it appears to overlap the first one and causes the program to read the wrong information.
I believe it has something to do with my realloc statement, although I have no idea what could be wrong. I tried to create a second array and realloc to that array, but that also failed.
int addContact(Contact *contacts, FILE *fptr, int size)
{
char *fName, *lName, *company, *email;
unsigned long phone;
long next;
char input[MAX_STRING_SIZE];
/* Gets the first name */
printf("First Name: ");
fgets(input, MAX_STRING_SIZE, stdin);
fName = toPointer(input);
/*Gets the last name or company name */
do
{
printf("Last Name: ");
fgets(input, MAX_STRING_SIZE, stdin);
lName = toPointer(input);
printf("Company Name: ");
fgets(input, MAX_STRING_SIZE, stdin);
company = toPointer(input);
} while ((lName[0] == '\0' || lName[0] == '\n') && (company[0] == '\0' || company[0] == '\n'));
/* Gets the phone number */
do
{
printf("Phone Number (enter only numbers): ");
fgets(input, MAX_STRING_SIZE, stdin);
if (input[0] != '\0' && input[0] != '\n')
{
sscanf(input, "%ld", &phone);
}
} while ((phone < 1000000 || phone > 9999999) && (phone < 1000000000 || phone > 9999999999));
do
{
printf("Email: ");
fgets(input, MAX_STRING_SIZE, stdin);
email = toPointer(input);
} while (!isValidEmail(email));
printf("Action: ");
fgets(input, MAX_STRING_SIZE, stdin);
lowerCase(input);
if (input[0] == 's' && input[1] == '\0')
{
next = getNext(fptr);
printf("Size: %d\n", size);
contacts = realloc(contacts, sizeof(Contact) * (size+1));
fseek(fptr, 0, SEEK_END);
/* Calculates the position for the contact */
contacts[size].phone_number = phone;
contacts[size].first_name_posn = next + sizeof(Contact);
contacts[size].last_name_posn = next + sizeof(Contact) + (sizeof(char) * (strlen(fName)+1));
contacts[size].company_name_posn = next + sizeof(Contact) + (sizeof(char) * (strlen(fName)+1)) + (sizeof(char) * (strlen(lName)+1));
contacts[size].email_posn = next + sizeof(Contact) + (sizeof(char) * (strlen(fName)+1)) + (sizeof(char) * (strlen(lName)+1)) + (sizeof(char) * (strlen(company)+1));
contacts[size].next = next + sizeof(Contact) + (sizeof(char) * (strlen(fName)+1)) + (sizeof(char) * (strlen(lName)+1)) + (sizeof(char) * (strlen(company)+1)) + (sizeof(char) * (strlen(email)+1));
fwrite(&contacts[size], sizeof(Contact), 1, fptr);
fwrite(fName, sizeof(char) * (strlen(fName)+1), 1, fptr);
fwrite(lName, sizeof(char) * (strlen(lName)+1), 1, fptr);
fwrite(company, sizeof(char) * (strlen(company)+1), 1, fptr);
fwrite(email, sizeof(char) * (strlen(email)+1), 1, fptr);
size++;
}
free(fName);
free(lName);
free(company);
free(email);
return size;
}
If I enter these two contacts:
First Name: John
Last Name: Smith
Company: Rick's
Phone: 1234567899
Email: jsmith@hotmail.com
First Name: Bob
Last Name: Evergreen
Company:
Phone: 5194567895
Email: bobgreen@gmail.com
This will rid the first name of John, and change the phone number to 6445449192 other staying the same for that contact. For the second contact, all the information is "om", and the phone number is 64.
