Double pointers in a linked list - c

Question

I'm trying to store a string in a linked list, but for some reason, I keep getting segmentaion fault error.
I've tried everything, and I feel I'm missing something really stupid and easy, please any thoughts?
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SIZE 60
typedef struct Node
{
char *getInput;
struct Node *next;
} Node;
typedef struct list
{
Node *head;
} list;
void readText(Node **a)
{
char c;
int i = 0;
while ((c = getchar()) != EOF)
(*a)->getInput[i++] = c;
}
void main()
{
Node *b;
b->getInput = (char *)calloc(SIZE, sizeof(char));
if (b == NULL)
{
printf("sadsa");
exit(1);
}
readText(&b);
printf("%s", b->getInput);
}

Answer 1

You mave to allocate a valid region and assign to b before dereferencing that.
Also checking if b is not NULL must be taken place before dereferencing.
You should use standard int main(void) in hosted environment instead of void main(), which is illegal in C89 and implementation-defined in C99 or later, unless you have some special reason to use non-standard signature.
getchar() returns int, so the return value should be assigned to an int variable. Otherwise, it will be difficult to distinguish between a valid character and EOF.
You should terminate strings by adding terminating null-character before using that for %s. (In this case it is not necessary because the buffer is initialized to zero via calloc(), but this will improve safety for another usage of the function)
void readText(Node **a)
{
int c; /* use proper type */
int i = 0;
while ((c = getchar()) != EOF)
(*a)->getInput[i++] = c;
(*a)->getInput[i] = '\0'; /* terminate the string */
}
int main(void) /* use standard signature */
{
Node *b = malloc(sizeof(*b)); /* allocate buffer */
if (b == NULL) /* check if allocation is successful before dereferencing */
{
printf("sadsa");
exit(1);
}
b->getInput = (char *)calloc(SIZE, sizeof(char));
readText(&b);
printf("%s", b->getInput);
}