I have a problem that I cannot find an actual solution after searching for about half a day. In this program, I have to fill an array of structs with customer information. I also have to do a couple other things, but I cannot figure out this bug in my code. I know the problem is the input buffer has a line feed or a new line character in the buffer after scanning in the quantity of customers. Many have suggested already online using:
while((number = getchar()) != '\n' && number != EOF)
/* discard the character */;
This only works for the first name entered, then I run into the same problem from the loop putting the new line or line feed from the customer priority. There needs to be a way that I can take out that line feed and not have to worry about it. I cannot use something like fflush(); or any functions like that.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#define MIN_CUSTOMERS 2 /* Minimum valid menu choice */
#define MAX_CUSTOMERS 100 /* Maximum valid menu choice */
#define MAX_NAME_LENGTH 21 /* Maximum last name length */
#define END_OF_STRING '\0' /* End of string character */
#define NEW_LINE '\n' /* New line character */
#define QUIT 0 /* Program exit value */
#define DB_ALLOC_ERROR 1 /* Database allocation error */
/**********************************************************************/
/* Program Structures */
/**********************************************************************/
/* A company customer record */
struct customer
{
char customer_name[MAX_NAME_LENGTH]; /* Last name of customer */
float amount_owed; /* Dollar amount customer owes */
int priority; /* Priority number of customer */
};
/**********************************************************************/
/* Function Prototypes */
/**********************************************************************/
void print_heading();
/* Print the heading of the program */
void print_instructions();
/* Print the program instructions */
int get_number_of_customers();
/* Get the number of customers to be recorded */
void get_customers(int quantity,
struct customer *p_customer_records_start);
/* Ask the user for customers and fills them into the database */
void clean_names(int quantity,
struct customer *p_customer_records_start);
/* Clean customer names of everything except letters and spaces */
void sort_customers(int quantity,
struct customer *p_customer_records_start);
/* Sort the array of customers alphabetically */
void print_customers(int quantity,
struct customer *p_customer_records_start);
/* Print the items in the customer database */
/**********************************************************************/
/* Main Function */
/**********************************************************************/
int main()
{
int quantity; /* Amount of customer databases */
struct customer *p_customer_records; /* Pointer to the database */
/* Print the program heading */
printf("\n\n\n\n\n\n");
print_heading();
/* Loop through the number of customer database */
while(print_instructions(),
(quantity = get_number_of_customers()) != QUIT)
{
/* Allocate memory for the experimental scientific data values */
/* and abort if memory is not available */
if((p_customer_records =
(struct customer*)malloc(sizeof(struct customer) * quantity))
== NULL)
{
printf("\nERROR NUMBER %d OCCURRED in main()", DB_ALLOC_ERROR);
printf("\nCould not allocate memory for experimental data");
printf("\nThe program is aborting");
exit(DB_ALLOC_ERROR);
}
/* Get, clean, sort, and print the database of customers */
get_customers(quantity, p_customer_records);
clean_names(quantity, p_customer_records);
sort_customers(quantity, p_customer_records);
print_customers(quantity, p_customer_records);
/* Display end of database processing */
printf("\n\n******* End of Customer Database Processing *******");
printf("\n");
/* Free the database memory that was allocated */
free(p_customer_records);
}
/* Print goodbye and terminate */
printf("\nThanks for processing accounts. Have a nice day! :-)");
return 0;
}
This is where I get the quantity.
/**********************************************************************/
/* Get number of customers */
/**********************************************************************/
int get_number_of_customers()
{
int quantity; /* Quantity of experimental scientific data values */
do
{
printf("\n\nGet the number of customers for the database");
printf("\n- - - - - - - - - - - - - - - - - - - - - - - - - -");
printf("\nHow many customers do you have (2 to 100, 0=quit): ");
scanf ("%d", &quantity);
} while (quantity == 1 ||
quantity < QUIT || quantity > MAX_CUSTOMERS);
return quantity;
}
/**********************************************************************/
/* Get customers information */
/**********************************************************************/
void get_customers(int quantity,
struct customer *p_customer_records_start)
{
struct customer *p_customer; /* Points to each customer */
char *p_last_name;
/* Loop through the array of customers and get information */
for(p_customer = p_customer_records_start;
(p_customer-p_customer_records_start) < quantity; p_customer++)
{
/* Get the customer's last name */
printf("\n- Customer Information -");
printf("\n Enter the customer's last name: ");
p_last_name = p_customer->customer_name;
This is where my problems come up.
do {
*p_last_name = getchar();
p_last_name++;
} while (*(p_last_name - 1) != NEW_LINE);
*(p_last_name - 1) = END_OF_STRING;
/* Get the amount the customer owes */
printf(" Enter the amount owed: ");
scanf ("%f", &p_customer->amount_owed);
/* Get the customer's priority */
printf(" Enter the customer's priority: ");
scanf("%d", &p_customer->priority);
while(p_customer->priority < 1 || p_customer->priority > 3)
{
printf(" Enter a valid priority (1-3): ");
scanf ("%d", &p_customer->priority);
}
If i use the while loop (previous explanation) here, the priority is never valid and an infinite loop begins.
}
return;
}
