OJ Board

can anybody help me to sort out the problem.I m getting runtime error again and again...:(
#include<stdio.h>
#include<iostream.h>

int main()
{
long long i=0,temp1,temp2,dif,flag;
int n,check=1;
struct node
{
long long data;
node *next;
}*list,*tmp,*last;
list=NULL;
while(scanf("%d",&n)==1)
{
flag ...