/*includes*/
 
#include <stdio.h>
#include <string.h>
#include <ctype.h>
 
//Structure containing all contact information fields
struct contact {
	char firstname [40]; 	//first name field
	char lastname [40]; 	//last name field
	char address [100]; 	//address field
	char postalcode [7]; 	//postal code field
	char phone[11];		//phone number field
struct contact *nextPtr; 	//pointer to next contact
}; 
 
struct student *pFirst = NULL; 
struct student *pLast = NULL;
 
/*Function Prototypes*/
int enterchoice (void);
int addnewcontact ();
int isvalidpostalcode (struct contact pPtr[]);
int isvalidphone (struct contact nPtr[]);
void flush_in ();
int filewrite ();
int displaydata ();
int loaddata ();
int finalsave ();
void formatphonenumber (struct contact *gPtr);
void formatpostalcode (struct contact *hPtr);
void wordcap (struct contact aPtr[]);
void search();
void ClearList(struct student *pF);
 
/*i defined globally as a counter*/
int i=1;
 
/* Main Module
Takes no input
goes to the enter choice menu
*/
int main (void){ 
 
int choice;
 
printf ("\n *** Personal Contact Book v1.0 *** \n");
 
enterchoice (); //go to the main menu
 
return 0; //return 0 indicating successful termination
}
 
//Choice Entering Module
//Takes integer as input
//according to users choice, it goes to 6 different modules
int enterchoice (void)
{
int choice;
 
 
  printf ("1)Add New Contact.\n2)Display Current Contacts.\n3)Search for a contact.\n4)Save Contacts to File.\n5)Load Contacts from File.\n6)Exit.\n");
  printf (">");
  scanf ("%d", &choice);
 
          switch (choice){ //starting switch case
                case 1:
                    addnewcontact(); //go to the adding a new contact module to add a new contact
                        break;
		case 2:
		    displaydata (); //go to the display contact module to display latest contact added
			break;
		case 3:
		    search(); //go to the contact search module to search for a saved contact
			break;
                case 4:
                     filewrite(); // go to the file saving module to save contacts inputted
                        break;
		case 5:
		     loaddata(); //go to the loading module to load and print saved contacts
			break;		
		case 6: finalsave();//go to the final save module to save whatever changes were made to the file
			break; 
                default: printf ("\nInvalid choice\n");
				enterchoice(); //if choice was invalid, inform user then re-display menu
					break;
		}
 
}
 
/*add new contact module
takes first name, last name,
address, postal code and phone 
number as input, after reading is done,
goes back to main menu*/
 
int addnewcontact () 
{
 
 struct contact * pNew = NULL;
 
char choice = 'y';	//defining local variables
    int z, y;
 
 pNew = (struct contact *) (malloc( sizeof( struct contact)));
 
 
FILE *outfile; 					//declaring file pointer
 
outfile = fopen ("contactlist.dat", "w"); 	//opening file
 
while (choice == 'y'){  			//start of outer while loop
	printf ("\nAdding new contact: \n");
 	printf ("First name: ");
	scanf("%s",pNew->firstname); 	//reading first name
 	printf ("Last name: ");
 	scanf("%s",pNew->lastname); 	//reading last name
 	printf ("Address: ");
 	flush_in();
 	gets (pNew->address); 		//reading address
 	printf ("Postal code: ");
 	scanf("%s",pNew->postalcode); 	//reading postal code
 
z = isvalidpostalcode (pNew->postalcode); //going to isvalidpostalcode module to validate postal code
 
//start of inner while loop, checking if inputted postal code is correct (module would return 1 in that case)
 
	while (z != 1){ 			
		printf ("Invalid postal code, please enter a correct one.\n"); 
		printf ("Postal code: ");
		scanf("%s",pNew->postalcode);
		flush_in();
		z = isvalidpostalcode (pNew->postalcode); //validate newly entered postal code
		}
	printf ("Phone number: ");
 	scanf("%s",pNew->phone); 				//reading phone number
 	flush_in();
 
y = isvalidphone (pNew->phone); 				//going to isvalidphone module to validate phone number
 
//start of third inner while loop, checking if inputted phone number is correct (module would return 1 in that case)
 
	while (y != 1){ 		
		printf ("Invalid phone number, Please enter a 10-Digit phone number starting with the area code.\n");
		printf ("Phone number: ");
		scanf("%s",pNew->phone); 			//reading new phone number
		flush_in();
		y = isvalidphone (pNew->phone);		 //validate newly entered phone number
		}
 
 
printf ("\nWould you like to enter a new contact? "); //see if user wants to enter another contact
scanf ("%c", &choice);
i++;//increment records counter
 
pNew->nextPtr = NULL;
 
if (pFirst == NULL)
	pFirst = pNew;
 
 if (pLast != NULL)
         pLast->nextPtr = pNew;
 
pLast = pNew;
}
 
ClearList (pFirst);
 
enterchoice (); //go back to main menu
 return 0;	//return 0 to indicate successful termination
}
 
/*This module takes the inputted 
postal code in the addnewcontact module
and validates it, returns 1 if
correct, or returns 0if incorrect*/
 
int isvalidpostalcode(struct contact pPtr[])
{
   int length = (int)(strlen(pPtr)); //finding the length of the passed string
 
   if (length == 6){ //if the length is 6 characters, check if the sequence is 'letter' 'number' 'letter' 'number' 'letter' 'number'
      if (isalpha(pPtr[0]) && isdigit(pPtr[1]) && isalpha(pPtr[2]) && isdigit(pPtr[3]) && isalpha(pPtr[4]) && isdigit(pPtr[5]))
      {
	return 1; //return 1 is this is true
	}
       else{
   return 0; //otherwise return 0
   } //end of inner else statement
 }
  else {
return 0; //otherwise if the length exceeds or is less than 6 return 0
 } //end of outer else statement
}
 
/*Validating phone number function,
takes passed phone number as input
returns 1 if its valid, and 0 if invalid*/
 
int isvalidphone (struct contact nPtr[])
{
   int length = (int)(strlen(nPtr)); //finding length of string
 
	if (length <= 10){ //if the length is less than or equal to 10 then check if sequence is 10 numbers
		if (isdigit(nPtr[0]) && isdigit(nPtr[1]) && isdigit(nPtr[2]) && isdigit(nPtr[3]) && isdigit(nPtr[4]) && isdigit(nPtr[5]) && isdigit(nPtr[6]) && isdigit(nPtr[7]) && isdigit(nPtr[8]) && isdigit(nPtr[9]))
		{
		  return 1; //return 1 if this is true
	        	}
		else{
		    return 0; //otherwise if its false return 0
		}//end of inner else statement
   	}
	else {
	return 0; //otherwise if length exceeds 10 digits, then return 0
	} //end of outer else statement
}
 
/*flush function, takes no input
and has no output*/
 
void flush_in (){ 
int ch;		//defining local variables
	while ((ch = fgetc (stdin))!= EOF && ch != '\n'){}
}
 
/*Contact information saving function
takes all contact information inputted in the
addnewcontact module, and prints them to the file*/
 
int filewrite (){
int u; //defining local variables, 
struct student *pF;
 
struct student *pC=pF;
FILE *xPtr; //defining file pointer
 
xPtr = fopen ("contactlist.dat", "w"); 			//opening file for writing
 
for (u=1;u<i;u++){ 					//going through the entire file
	fprintf (xPtr,"%s\n", pC->firstname);	//writing first name
	fprintf (xPtr,"%s\n", pC->lastname);	//writing last name
	fprintf (xPtr,"%s\n", pC->address);	//writing address
	fprintf (xPtr,"%s\n", pC->postalcode);	//writing postal code
	fprintf (xPtr,"%s", pC->phone);		//writing phone number
	}
 
fclose (xPtr);//closing file
 
printf ("\nContact information saved successfully!\n"); //informing user that the process was a success
printf ("\n");
enterchoice ();		//going back to the main menu
return 0;
}
 
/*Data display function,
outputs the last contact information 
entered, takes input from addnewcontact module*/
 
int displaydata (struct student *pF){
//defining local variables
int j;
j=i-1;
 
struct student *pC = pF;
 
printf ("\n");
printf ("First name: ");
wordcap (pC->firstname); 		//capitalizing then printing last first name entered
printf ("Last name: ");
wordcap (pC->lastname);			//capitalizing then printing last last name entered
printf ("Address: %s\n", pC->address);	//printing last address entered
printf ("Postal code: ");
formatpostalcode (pC->postalcode);	//formatting then printing last postal code entered
printf ("Phone number: ");
formatphonenumber (pC->phone);		//formatting then printing last postal code entered
 
printf ("\n");
enterchoice();			// going back to main menu
}
 
/*Loading function, takes input saved into the file
from the filewrite function and reads it from the file
then prints it to the user*/
 
int loaddata (){
//declaring local variables
int u=1;
 
FILE *cPtr; //defining file pointer
 
cPtr = fopen ("contactlist.dat", "r"); //opening file for reading
 
	if (cPtr == '\0'){ 		//if file is empty, then inform user
	printf ("Error, File is empty\n");
	}
 
	else{ //otherwise read from file and print
 
//while the end of the file is not reached, and the maximum number of records has not been reached either, print the information
 
	while (!feof(cPtr) && u < i) 
		{	
			fgets (contact[u].firstname, 40, cPtr); 	//read the first name
			wordcap (contact[u].firstname); 		//captitalize it then print it			
			fgets (contact[u].lastname, 40, cPtr);		//read last name
			wordcap (contact[u].lastname);			//capitalize it then print it
			fgets (contact[u].address, 100, cPtr);		//read address 
			printf ("%s\n", contact[u].address);		//print address
			fgets(contact[u].postalcode, 7, cPtr);		//read postal code
			formatpostalcode (contact[u].postalcode);	//format it then print it
			fgets (contact[u].phone, 10, cPtr);		//read phone number
			formatphonenumber (contact[u].phone); //BUG: prints first contacts phone number incorrectly, then prints correctly for other contacts
			printf ("\n");
			u++;
			cPtr++;
			}
 
 
 
	fclose (cPtr);
  	}
   enterchoice ();
}
 
/*Final save function, 
prompts user if he/she wants 
to save any unsaved changes in his/her
contact information, takes choice as input,
writes unsaved information to file*/
 
int finalsave ()
{
 
//declaring local variables
char choice; //declaring choice variable
int u; //declaring counter
 
FILE *outfile; //declaring file pointer
 
printf ("Would you like to save your contacts before leaving? "); //prompting user if he/she wants to save unsaved changes
 
scanf ("%s", &choice); //reading users response
 
if (choice == 'y') //if user responds y as in yes, then open the file, and save all contact information
{ 
	outfile = fopen ("contactlist.dat", "w"); 	//opening file
		for (u=1;u<i;u++){ 			//going through all contents of file
			fprintf (outfile,"%s\n", contact[u].firstname);		//writing first name
			fprintf (outfile,"%s\n", contact[u].lastname);		//writing last name
			fprintf (outfile,"%s\n", contact[u].address);		//writing address
			fprintf (outfile,"%s\n", contact[u].postalcode);	//writing postal code
			fprintf (outfile,"%s\n", contact[u].phone);		//writing phone number
			}	//end of for loop
	fclose (outfile); //closing file
	printf ("\nContact information saved successfully!\n");		//inform user operation was successful
	printf ("\n");
	}
printf ("Bye!\n"); 
return 0; 		//return 0 indicating successful termination
}
 
/*Formatting phone number module
Takes passed phone number, and puts area code
in brackets, then puts a space, and a hyphen character 
3 numbers after that*/
 
void formatphonenumber (char *gPtr){
//declaring counters
int k, j, l; 
 
putchar ('(');		//inputting opening bracket before first 3 numbers
 
for (k = 0; k < 3; k++){ 	//going through first 3 numbers
	putchar(gPtr[k]);	//print them
	}	//end of for loop
 
putchar (')'); 		//input a closing bracket after 3 numbers have been printed
putchar (' ');		//input a space after the closing bracket has been printed
 
	for (j = 3; j < 6; j++){	//going through 3 more numbers, printing as we go
		putchar(gPtr[j]);
		}
	putchar ('-');				//after 3 more numbers have been printed, input a hyphen
 
		for (l = 6; l < 10; l++){	//go through the last 4 numbers, print as we go
			putchar(gPtr[l]);
			}
		printf ("\n");
}
 
 
/*formatting postal code,
works almost same way as the 
formatphonenumber function;
takes passed postal code, 
capitalizes the letters and inputs a 
hyphen after 3 characters have 
been printed*/
 
void formatpostalcode (char *hPtr){	
//declaring local variables
int f, g; //declaring counters
char c, k, d;
 
for (f = 0; f <3; f++){		//going through first 3 characters, converting to uppercase and printing as we go
	c = toupper (hPtr[f]);
	putchar (c);
	} 			//end of for loop
 
putchar ('-');			//input hyphen after 3 characters have been printed
 
for (g = 3; g < 6; g++){	//go through last 3 letters, converting to uppercase and printing as we go
	c = toupper (hPtr[g]);
	putchar (c);
	}			//end of for loop
printf ("\n");
}
 
/*Search function, takes 
last name as input, and ouputs
the record with a last name 
that matches the inputted last name*/
 
void search (){
 
//declaring local variables
char lname[40];		//declaring last name variable 
int u, choice;	//counter and choice variables, respectively
 
printf ("Please enter contacts last name: ");	//prompting user to input last name
scanf ("%s", lname);
 
FILE *outfile;	//declaring file pointer
 
outfile = fopen ("contactlist.dat", "rt");	//opening file
 
for (u=0; u<=i;u++){		//going through contents of file
 
   if (strcmp (lname, contact[u].lastname)== 0){	//if last name is found, then print all information that accompanies it
	printf ("\nFirst Name: ");
	wordcap (contact[u].firstname);
	printf ("Last Name: ");
	wordcap(contact[u].lastname);
	printf ("Address: %s\n", contact[u].address);
	printf ("Postal Code: ");
	formatpostalcode (contact[u].postalcode);
	printf ("Phone Number: ");
	formatphonenumber (contact[u].phone);
 
	}
fclose (outfile);	//closing file
     }
printf ("\n");
enterchoice();		//back to main menu
}
 
/*wordcap function, words similarily to 
formatphonenumber and formatpostalcode,
takes passed word as input, and outputs 
its first letter capitalized*/
 
void wordcap (char aPtr[]){
 
//declaring local variables
int k, l; 	//declaring counters
char c;
char d;
int length = ((int) strlen(aPtr));	//finding length of passed word
 
for (k = 0; k < 1; k++){	//going to beginning of the string and capitalizing first character
	c = toupper (aPtr[k]);
	putchar (c);			//printing capitalized character
	}
		for (l = 1; l < length;l++){	//going through rest of string and changing everything to lower case along with it
		d = tolower (aPtr[l]);
		putchar(d);
		}
printf ("\n");
}

PrevNode->next = cntctPtr;

cout << "Enter Name: ";
cin >> cntctPtr->name;
etc..
...

//Start at the front of the list and work to the back
contact *temp = headptr;
 
while(strcmp(temp->name, target_name) != 0 && temp != NULL)
{
     temp = temp->next;
}
 
//At this point, as long as temp does not equal NULL, 'temp' should be the node ye' are looking for.

contact *temp = headptr;
 
while(headptr != NULL)
{
     headptr = temp->next;
     delete temp;
}