Code:
#include <stdio.h>
#include <stdlib.h>
char choice, firstname, lastname, phonenumber, comporg, email, search;
// Definition of node for holding customer info
struct customer {
char firstname;
char lastname;
char phonenumber;
char comporg;
char email;
struct customer *next;
};
typedef struct customer Customer;
typedef Customer *Customerptr;
// Function prototypes:
void loadmainmenu ();
void add( Customerptr *headOfList, char firstname, char lastname, char phonenumber, char comporg, char email );
char delete( Customerptr *headOfList, char fname, char lname );
void loadsearchmenu ();
void print( Customerptr *headOfList);
void printlist( Customerptr *headOfList );
int isEmpty( Customerptr cptr );
// Main program:
int main(void) {
Customerptr startptr = NULL;
loadmainmenu();
printf("Your choice? \n");
scanf("%c", choice);
while ( choice != 'e' || choice != 'E' ) {
// Evaluates menu options
switch (choice) {
// Displays add customer submenu:
case 'A':
case 'a':
printf("Add Submenu: \n\n");
printf("Please input First Name: \n");
scanf ("%c \n", &firstname);
printf("Please input Last Name: \n");
scanf ("%c \n", &lastname);
printf("Please input Phone Number: \n");
scanf ("%c \n", &phonenumber);
printf("Please input Company/Organization: \n");
scanf ("%c \n", &comporg);
printf("Please input Email: \n\n");
scanf ("%c \n", &email);
add(&startptr, firstname, lastname, phonenumber, comporg, email);
printf("A new customer has been added \n");
break;
// Displays remove customer submenu:
case 'R':
case 'r':
printf("Remove Submenu \n");
if ( !isEmpty( startptr )) {
printf("Please input First Name: \n");
scanf ("%c \n", &firstname);
printf("Please input Last Name: \n\n");
scanf ("%c \n", &lastname);
}
if ( delete( &startptr, firstname, lastname ) ) {
printf("%c %c has been removed from the system. \n", firstname, lastname);
}
break;
case 'S':
case 's':
printf("Search Submenu \n");
if ( !isEmpty( startptr )) {
printf("Please input the customer’s First or Last name: \n");
scanf ("%c \n", &search);
}
else
print (&startptr);
break;
// Displays display customer submenu:
case 'D':
case 'd':
if ( !isEmpty( startptr )) {
printf("Display Submenu \n");
printlist( &startptr );
}
printf("All customers are displayed: \n");
break;
case 'E':
case 'e':
exit(0);
break;
default:
printf("You entered an invalid choice! \n");
printf("Please try again ... \n");
loadmainmenu();
break;
}
}
}
// Displays main menu options:
void loadmainmenu() {
printf("Main Menu: \n\n");
printf("(a) Add a customer \n");
printf("(r) Remove a customer \n");
printf("(s) Search a customer \n");
printf("(d) Display all customers' information \n");
printf("(e) Exit \n\n");
}
// Adds customer name to database
void add( Customerptr *headOfList, char firstname, char lastname, char phonenumber, char comporg, char email ) {
Customerptr newPtr;
Customerptr previousPtr;
Customerptr currentPtr;
newPtr = ( Customer * ) malloc( sizeof( Customer ) );
if ( newPtr != NULL ) {
newPtr->firstname = firstname;
newPtr->lastname = lastname;
newPtr->phonenumber = phonenumber;
newPtr->comporg = comporg;
newPtr->email = email;
newPtr->next = NULL;
previousPtr = NULL;
currentPtr = *headOfList;
if ( currentPtr != NULL ) {
previousPtr = currentPtr;
currentPtr = currentPtr->next;
}
if ( previousPtr == NULL ) {
newPtr->next = *headOfList;
*headOfList = newPtr;
}
else {
previousPtr->next = newPtr;
newPtr->next = currentPtr;
}
}
else {
printf( "%c %c not inserted. There is no memory available.\n", firstname, lastname);
}
}
// Deletes customer from database
char delete( Customerptr *headOfList, char fname, char lname ) {
Customerptr previousPtr;
Customerptr currentPtr;
Customerptr tempPtr;
if ( ( fname == ( *headOfList )->firstname ) && ( lname == ( *headOfList )->lastname ) ) {
tempPtr = *headOfList;
*headOfList = ( *headOfList )->next;
free( tempPtr );
tempPtr = *headOfList;
*headOfList = ( *headOfList )->next;
free( tempPtr );
return fname, lname;
}
else {
previousPtr = *headOfList;
currentPtr = ( *headOfList )->next;
while ( ( currentPtr != NULL && currentPtr->firstname != fname ) && ( currentPtr != NULL && currentPtr->lastname != lname ) ) {
previousPtr = currentPtr;
currentPtr = currentPtr->next;
}
if ( currentPtr != NULL ) {
tempPtr = currentPtr;
previousPtr->next = currentPtr->next;
free( tempPtr );
tempPtr = currentPtr;
previousPtr->next = currentPtr->next;
free( tempPtr );
return fname, lname;
}
}
return '\0';
}
void searchlist () {
}
void print( Customerptr *headOfList) {
printf("First name: ->%s \n", ( *headOfList )->firstname );
printf("Last name: ->%d \n", ( *headOfList )->lastname );
printf("Phonenumber: ->%d \n", ( *headOfList )->phonenumber );
printf("Company/Organization: ->%d \n", ( *headOfList )->comporg );
printf("Email: ->%d \n\n", ( *headOfList )->email );
}
void printlist( Customerptr *headOfList ) {
Customerptr currentPtr;
while( currentPtr != NULL )
{
print( headOfList );
*headOfList = ( *headOfList )->next;
}
}
int isEmpty( Customerptr cptr ) {
return cptr == NULL;
}
writefile(Customerptr *headOfList ) {
Customerptr currentPtr;
FILE *fp;
char c;
fp = fopen("customers.txt", "w");
if (fp == NULL) { // If file doesn't exist
printf("Cannot open file. \n");
return(0);
}
while( currentPtr != NULL )
{
fprintf (fp, "%s \n" , print( headOfList ));
*headOfList = ( *headOfList )->next;
}
}
My question is, in adding the linked list to the file, what am I doing wrong? & Also when searching the linked list to display the results with either first or last name, say for example "Feng", displays all results with first or last name "Feng".
Help with menu & Linked list
