Segmentation fault when deleting linked list - c

Question

I am trying to delete all the nodes on a linked list but I am getting a segmentation fault.
I had code that was working initially but I was only deleting the first node in the list, I want to delete all the nodes and delete all the pointers redundant pointers.
Also if some of you guys could check the function I am using to create the linked list and give me some feedback on whether you think it is ok or where some improvements could be made, I would appreciate it.
Thanks.
Here is the code:
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#define MEMORY_SIZE (15)
typedef struct link {
double coeff;
int pow;
struct link * next;
} poly;
poly *polyArray[MEMORY_SIZE];// array of 15 polynomials to play with
// /** The function prototypes */
void createPoly(poly **);
void deletePoly(poly *);
/**
* The main function
*/
int main(void) {
printf("\n\n\t***************************************************");
/* printf("\n\tDemonstrating Polynomial Creation");
printf("\n\t***************************************************");*/
printf("\n\t1st polynomial\t");
createPoly(&polyArray[0]);
showPoly(polyArray[0]);
srand(time(NULL));
// printf("\n\n\tCreating and storing the 2nd polynomial\n");
// createPoly(&polyArray[1]);
// showPoly(polyArray[1]);
showPoly(polyArray[0]);
printf("\n\t***************************************************");
printf("\n\tProgram has Ended, Deleting all polynomials");
printf("\n\t***************************************************");
int count;
for(count = 0; count < MEMORY_SIZE; count++)
{
deletePoly(polyArray[count]);
}
printf("\n\n");
showPoly(polyArray[0]);
return 0;
}//end main function
//////////////////////////////////////////////////////////////////////////////////////
void createPoly(poly **node) {
poly *tempnode; //To hold the temporary last address
tempnode = (poly*)malloc( sizeof(poly) ); //create the first node
*node = tempnode; //Store the head address to the reference variable
int flag = 1 + rand()%3;; // A flag to control the number of terms
int counter;
for( counter = 0; counter <= flag; counter++ )
{
tempnode->pow = ( flag-counter );
tempnode->coeff = ( (double)(rand()%20) )/( (double)(1 + rand()%20) );
if( (counter < flag) && (counter >= 0) )
{
tempnode->next = (poly*)malloc( sizeof(poly) ); //Grow the list
}
else if ( counter == flag )
{
tempnode->next = NULL;
}
tempnode = tempnode->next;
}
}
void deletePoly(poly *node) {
poly *temp;
if( node->next == NULL )
{
free( node );
node = NULL;
}
else
{
while( node->next != NULL )
{
temp = node->next;
free( node );
node = temp;
}//end while
node = NULL;
}//end 'if/else'
}//end function 'deletePoly'

Answer 1

As I understand it, the main function is creating only the first polynomial (poly[0]), but you are trying to delete them all (the loop in the main function goes up to MEMORY_SIZE).
You should also initialize all your pointers to NULL before beginning the program (this is an important feature in C programs) and change the deletePoly this way:
void deletePoly(poly *node) {
poly *temp;
while( node != NULL ) {
temp = node->next;
free( node );
node = temp;
}//end while
node = NULL;
}//end function 'deletePoly'