Creating Linked-list of characters and printing it - c

Question

I'm trying to implement a Linked list using this code.This code complies successfully but results in Segmentation fault (core dumped) error.How can I resolve this?
#include<stdio.h>
#include<stdlib.h>
struct node{
char ch;
struct node *next;
};
struct node *head=(struct node *)malloc(sizeof(struct node));
struct node *p1=NULL;
void addnode(char ch) {
if(head==NULL) {
head->ch=ch;
head->next=NULL;
}
else {
struct node *New=(struct node *) malloc (sizeof(struct node));
for(p1=head;p1->next!=NULL;p1=p1->next);
p1->next=New;
}
}
void main() {
char ch,frm,to;
printf("\nEnter the string");
while((ch=getchar())!='\0')
addnode(ch);
for(p1=head;p1!=NULL;p1=p1->next)
printf("\n%c",p1->ch);
}

Answer 1

Simple Mistakes first: When you allocate memory in global you initiate a function call(malloc is also a function). Function calls can only be made inside main or other funcitons. So just declare head don't use malloc in global.
#include<stdio.h>
#include<stdlib.h>
struct node{
char ch;
struct node *next;
};
struct node *head=NULL;
struct node *p1=NULL;
void addnode(char ch) {
if(head==NULL) {
struct node *New=(struct node *) malloc (sizeof(struct node));
head=New;
New->ch=ch;
New->next=NULL;
}
else {
struct node *New=(struct node *) malloc (sizeof(struct node));
New->ch=ch;
New->next=NULL;
for(p1=head;p1->next!=NULL;p1=p1->next);
p1->next=New;
}
}
void main() {
char ch,frm,to;
printf("\nEnter the string");
while((ch=getchar())!='\n')
addnode(ch);
for(p1=head;p1!=NULL;p1=p1->next)
printf("\n%c",p1->ch);
}
Second mistake: Inside your addnode function when you chekk if head is null or not allocate some memory and assign it to head.
Third mistake: in your getchar() check until you find a new line not null character.
Fourth mistake: Assign ch to New and set New->next=null. You almost completely forgot that.

Answer 2

This worked better and I over came the errors :). And i missed pointers clarity there, which were rectified here..
#include<stdio.h>
#include<stdlib.h>
struct Node{
char ch;
struct Node *next;
};
struct Node head={'\0',NULL};
struct Node *p1=NULL;
void add(char ch){
if(head.ch=='\0')
head.ch=ch;
else{
struct Node *new=(struct node *)malloc(sizeof(struct Node));
new->ch=ch;
for(p1=&head;p1->next!=NULL;p1=p1->next);
p1->next=new;
}
}
void main(){
char c;
while((c=getchar())!='\n')
add(c);
for(p1=&head;p1!=NULL;p1=p1->next)
printf("%c\n",p1->ch);
}
But i still receive a warning saying,
initialization from incompatible pointer type [enabled by default]
struct Node *new=(struct node *)malloc(sizeof(struct Node));
^

Answer 3

I am not sure this is c way..but you have to think your code over how to release your allocated pointer...like free list function maybe..
Here is my way.
#include<stdio.h>
#include<stdlib.h>
struct node{
char ch;
struct node *next;
};
struct node * addnode(struct node *head, struct node *p1, char ch) {
if(head==NULL) {
printf("......return 2... \r\n");
head=(struct node *)malloc(sizeof(struct node));
head->ch=ch;
head->next=NULL;
return head;
}
else {
struct node *New=NULL;
printf("......return ... \r\n");
New=(struct node *) malloc (sizeof(struct node));
New->ch = ch;
New->next=NULL;
for(p1=head;p1->next!=NULL;p1=p1->next);
p1->next=New;
return head;
}
}
void main() {
char ch,frm,to;
struct node *head=NULL, *p1=NULL;
printf("\nEnter the string \n");
while((ch=getchar())!='q')
head = addnode(head, p1, ch);
for(p1=head;p1!=NULL;p1=p1->next)
{
printf("\n%c",p1->ch);
}
}
Another one.
#include<stdio.h>
#include<stdlib.h>
typedef struct node{
char ch;
struct node *next;
} *pNODE, NODE;
pNODE addnode2(pNODE head, pNODE p1, char ch) {
if(head==NULL) {
printf("......return 2... \r\n");
head=(pNODE)malloc(sizeof(NODE));
head->ch=ch;
head->next=NULL;
return head;
}
else {
struct node *new=NULL;
printf("......return ... \r\n");
new=(pNODE) malloc (sizeof(NODE));
new->ch = ch;
new->next=NULL;
for(p1=head;p1->next!=NULL;p1=p1->next);
p1->next=new;
return head;
}
}
void main() {
char ch,frm,to;
pNODE head=NULL;
pNODE p1=NULL;
printf("\nEnter the string \n");
while((ch=getchar())!='q')
head = addnode2(head, p1, ch);
for(p1=head;p1!=NULL;p1=p1->next)
{
printf("\n%c",p1->ch);
}
}