Thread: simple Linked Lists help

hey everyone,

im just trying to add a new node to the end of this list and print the list out...can someone tell me what i am doing wrong..thanks alot

Code:

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

struct listNode { 
	char data;
	struct listNode *nextPtr;
};

typedef struct listNode LISTNODE;
typedef LISTNODE *LISTNODEPTR;

/*prototypes*/
void insert(LISTNODEPTR *, char);
void printList(LISTNODEPTR); 

int main(void) {
	
	LISTNODEPTR startPtr = NULL;
	char nodedata;
	
	printf("\nEnter the letter you would like to add to the list\n");
	
	while(scanf("%d",&nodedata)) {
		printf("\nSorry thats not a letter or string\n");
	}

	insert(&startPtr, nodedata);
	printList(startPtr);

}

void insert(LISTNODEPTR *sPtr, char value) {

	LISTNODEPTR newPtr;
	LISTNODEPTR previousPtr;
	LISTNODEPTR currentPtr;

	if((newPtr = malloc(sizeof(LISTNODE))) == NULL) {

		printf("NOT ENOUGH MEMORY TO CREATE A NEW NODE OF %d SIZE", sizeof(LISTNODE));
		exit(1);

	}

	newPtr->data = value;
	newPtr->nextPtr = NULL;

	previousPtr = NULL;
	currentPtr = *sPtr;

	while(currentPtr != NULL) {

		previousPtr = currentPtr;
		currentPtr = currentPtr->nextPtr;

	}

	if(previousPtr == NULL) {

		*sPtr->nextPtr = newPtr; 
		
	}

	else {
		
		previousPtr->nextPtr = newPtr;		

	}

}

void printList(LISTNODEPTR currentPtr) {

	if(currentPtr == NULL) {

		printf("List is empty");
		exit(1);

	}

	else{
		
		printf("\nList Contains:");

		while(currentPtr != NULL) {

			printf("%s -->", currentPtr->data);
			currentPtr = currentPtr->nextPtr;

		}
}







}

hi all,

i still couldnt fix the bug...so ive just tried to copy an example out of a textbook.. the code below simply puts the letter a in a list ...and then i attempt to print the list...when i try to print the list is shows no output....can someone please help..thanks

Code:

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

struct listNode { 
	char data;
	struct listNode *nextPtr;
};

typedef struct listNode LISTNODE;
typedef LISTNODE *LISTNODEPTR;

/*prototypes*/
void insert(LISTNODEPTR *, char);
void printList(LISTNODEPTR); 

int main(void) {
	
	LISTNODEPTR startPtr = NULL;
	char nodedata = 'a';
	
	insert(&startPtr, nodedata);
	printList(startPtr);
	
	return 0;

}

void insert(LISTNODEPTR *sPtr, char value) {

	LISTNODEPTR newPtr;
	LISTNODEPTR previousPtr;
	LISTNODEPTR currentPtr;

	if((newPtr = malloc(sizeof(LISTNODE))) == NULL) {

		printf("NOT ENOUGH MEMORY TO CREATE A NEW NODE OF %d SIZE", sizeof(LISTNODE));
		exit(1);

	}

	newPtr->data = value;
	newPtr->nextPtr = NULL;

	previousPtr = NULL;
	currentPtr = *sPtr;

	while(currentPtr != NULL) {

		previousPtr = currentPtr;
		currentPtr = currentPtr->nextPtr;

	}

	if(previousPtr == NULL) {

		newPtr->nextPtr = *sPtr;
		*sPtr = newPtr;
	}
	
	else {
		
		previousPtr->nextPtr = newPtr;
		newPtr->nextPtr = currentPtr;

	}

}

void printList(LISTNODEPTR currentPtr) {

	if(currentPtr == NULL) {

		printf("List is empty");
		exit(1);

	}

	else{
		
		printf("\nList Contains:");

		while(currentPtr->nextPtr != NULL) {

			printf("%s -->", currentPtr->data);
			currentPtr = currentPtr->nextPtr;

		}
                 }

}