Fill a linked list char by char

Hi, I am writing a contact book program using linked lists and I want to fill the
elements of the lists character by character. The reason I want to do it char by char
is to allow spaces when I store strings for example when someone has a first name
like Bobby Joe or when entering an address like 123 Any Street.

Is this possible?

I know how to add strings without spaces, but my attempt at char by char is
resulting in Seg faults.

Here is my attempt:

Code:

include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>

struct contact					//structure declaration
{
	char fname[41];				//stores contacts first names
	char lname[41];				//stores contacts last names
	char address[101];			//stores contacts address
	char pcode[7];				//stores contacts postal code
	char phone[11];				//stores contacts phone number
	struct contact *ptrNext;	//self-referential pointer
};
typedef struct contact Con;	//type declaration

//declare global variables
struct contact *ptrFirst = NULL;
struct contact *ptrLast = NULL;

//function prototypes
struct contact *CreateCon();
struct contact *InputCon(Con *ptrNew);
void AddNew(Con *ptrNew);
int isEmptyList();

struct contact *InputCon(struct contact *ptrNew)
{
	char c;						//stores characters
	int pos;					//array position variable
	int spcount;				//space counter
	int digcount;				//digit counter

	fflush(stdin);				//flush the input buffer
	printf("FIRSTNAME: ");		//prompt the user
	pos = 0;					//reset counters
	spcount = 0;
	digcount = 0;
	while( ( c = getchar() ) != '\n' )		//do until user hits enter
	{
		ptrNew->fname[pos] = c;
		
		if( isspace(&ptrNew->fname[pos]))
		{
			spcount++;				//if its a space, count it
		}
		if( isdigit(&ptrNew->fname[pos]))
		{
			digcount++;				//if its a digit count it
		}
		pos++;						//increment the position
		//check the limit of the field
		if(pos>39)
		{
			break;		//if you reach the limit break
		}
	}
	ptrNew->fname[pos] = '\0';	//add string terminator
.
.
....roughly the same for last name, address, postal code and phone.
}

//Add new contact data interactively from the keyboard
//Input: a self-referencing pointer to the new instance
//Output: stores the data into the structure at that instance
void AddNew(Con *ptrNew)
{
	if (isEmptyList())
	{
		ptrFirst = ptrNew;
		ptrLast = ptrNew;
	}
	else
	{
		ptrNew->ptrNext = ptrFirst;
		ptrFirst = ptrNew;
	}
}

//check to see if the List is Empty
//Input: none
//Output: a boolean value for true or false
int isEmptyList()
{
	if(ptrFirst == NULL)
		return 1;
	else 
		return 0;
}


//function call in the program looks like...

			case 1: // user typed 1 Add New Contact
				
				while((another == 'Y') || (another == 'y'))
				{
					another = 0;
					AddNew(InputCon(CreateCon()));		//function call
					num++;					//increment number of contacts
					//let the user know the contact was added
					printf("\nThe contact was added successfully.\n");
					fflush(stdin);			//flush the input buffer
					//prompt the user for input
					printf("\nAdd another contact? (Yes = y, No = Any Key)\n");
					another = getchar();		//get user input
				}

Any ideas how I can make this work? I would really appreciate some insight.
I'm not looking for a fully coded solution, psuedocode that points me in the right
direction would be great. I just don't know how to use the pointers right to
correctly store the value.

Originally Posted by w2look

Hi, I am writing a contact book program using linked lists and I want to fill the
elements of the lists character by character. The reason I want to do it char by char
is to allow spaces when I store strings for example when someone has a first name
like Bobby Joe or when entering an address like 123 Any Street.

I'm going to hazard a guess here and say that this may be the tragic consequence of believing that there are only two commands for input in C (scanf, which is implicit in your fear of spaces, and getchar(), which you actually use).

You can use fgets() with stdin; this will get you a complete line, spaces, punctuation, whatever you can type. It will include the newline.

Code:

char name[32];
fgets(name,31,stdin);   /* leave one byte for null terminator */
name[strlen(buffer)]='\0';  /* get rid of \n */

If that is all you need to do, spare yourself this headache. Or have I misunderstood the goal?

Thanks, that was actually my next question.
I'll give gets a whirl and see if I can make it work.

Thanks for the suggestion!

I tried:

Code:

	fgets(ptrNew->fname,40,stdin) ;
	ptrNew->fname[strlen(ptrNew->fname)]='\0';

And it seems to work for as far as I have reached in the program thus far.
If I run into further troubles, I'll post them here.

ptrNew->fname[strlen(ptrNew->fname)]='\0';

this line is meaningless

for any C-string
str[strlen(str)] == 0

so overwriting 0 with 0 has no point at all

Yeah, I have since figured that out.

However, for my own purposes, I wanted to get rid of the \n being stored at the
end of the string so I'm using it like:

Code:

ptrNew->fname[(strlen(ptrNew->fname))-1]='\0';

and it seems to be doing what I want it to.
If you know a reason why I should not do this, please post.

>If you know a reason why I should not do this, please post.
If there is no '\n' there it will truncate the string by one.

You have to find the '\n' and replace it if it is there, anything else is brittle. This is a FAQ.