My application crashed without any error, problem with for loop(?) - c

Question

My teacher gave me a library that describes a single linked list. I am writing a main file to test it, and i ran into a very weird problem.
This is the header for the linked list library (There are more function, but i only putin the one i used):
#ifndef DSSINGLYLINKEDLIST_H
#define DSSINGLYLINKEDLIST_H
#ifdef __cplusplus
extern "C" {
#endif
typedef struct _SListEntry SListEntry;
typedef struct _SListIterator SListIterator;
typedef void *SListValue;
/**
* Definition of a #ref SListIterator.
*/
struct _SListIterator {
SListEntry **prevNext;
SListEntry *current;
};
#define SLIST_NULL ((void *) 0)
typedef int (*SListCompareFunc)(SListValue value1, SListValue value2);
typedef int (*SListEqualFunc)(SListValue value1, SListValue value2);
SListEntry *slist_append(SListEntry **list, SListValue data);
SListValue slist_nthData(SListEntry *list, unsigned int n);
unsigned int slist_length(SListEntry *list);
#ifdef __cplusplus
}
#endif
#endif /* #ifndef DSSINGLYLINKEDLIST_H */
This is my .c file:
#include <stdlib.h>
#include <stdio.h>
#include "dssinglylinkedlist.h"
struct _SListEntry {
SListValue data;
SListEntry *next;
};
SListEntry *slist_append(SListEntry **list, SListValue data)
{
/* Create new list entry */
SListEntry *newEntry = malloc(sizeof(SListEntry));
if (newEntry == NULL) {
return NULL;
}
newEntry->data = data;
newEntry->next = NULL;
/* Hooking into the list is different if the list is empty */
SListEntry *rover;
if (*list == NULL) {
/* Create the start of the list */
*list = newEntry;
} else {
/* Find the end of list */
rover=*list;
while (rover->next != NULL) {
rover = rover->next;
}
/* Add to the end of list */
rover->next = newEntry;
}
return newEntry;
}
SListValue slist_nthData(SListEntry *list, unsigned int n)
{
/* Find the specified entry */
SListEntry *entry = slist_nthEntry(list, n);
/* If out of range, return NULL, otherwise return the data */
if (entry == NULL) {
return SLIST_NULL;
} else {
return entry->data;
}
}
unsigned int slist_length(SListEntry *list)
{
SListEntry *entry = list;
unsigned int length = 0;
while (entry != NULL) {
/* Count the number of entries */
++length;
entry = entry->next;
}
return length;
}
I think there's nothing wrong with these code.
I am writing a main using this library to store information of two polynomial:
#include <stdio.h>
#include <stdlib.h>
#include "dssinglylinkedlist.h"
void printPolynomial(SListEntry*);
int main()
{
SListEntry *poly1;
int n;
printf("Input n for poly1: ");
scanf("%d", &n);
printf("Input poly1: ");
for (int i=0; i<=n; i++) {
int *temp = (int *) malloc(sizeof (int));
scanf("%d", temp);
slist_append(&poly1, temp);
}
printPolynomial(poly1);
SListEntry *poly2;
printf("Input n for poly2: ");
scanf("%d", &n);
printf("Input poly2: ");
// for (int i=0; i<=n; i++) {
// int *temp = (int *) malloc(sizeof (int));
// scanf("%d", temp);
// slist_append(&poly2, temp);
// }
// printPolynomial(poly2);
return 0;
}
void printPolynomial(SListEntry *list)
{
int length = (int)slist_length(list);
for (int i = 0; i < length; i++) {
int temp = *((int *)slist_nthData(list,(unsigned int)i));
if (i >0 && temp >= 0) {
printf("+");
}
printf("%d*x^%d", temp, length-i-1);
}
printf("\n");
}
So if i comments the second loop (after i print 'Input poly2', like i wrote above), i can still input my poly1 and print it. But if i un-comments it, my program crashes immediately when i append the first element of poly1.
What is the problem of my code?