OJ Board

Why WA, where am I wrong?

#include <stdio.h>
#include <iostream>
#include <iterator>
using namespace std;
int main()
{
int n;
while(scanf("%d",&n)&&n!=0){
std::istream_iterator<int> int_it(cin),end;
int sum=*int_it++;
for(int i=2;i<n;++i)
{
sum+=*int_it++;
if(sum<0)
sum=0;
}
sum+=*int ...

My code generates all the correct outputs,.. still getting WA. Can anyone figure out where am I wrong.... Got that.. thanks brian fry. I didnt notice my first char is a null. cmd in windows showed that as space :/

My code does provide all the sample output. but where it is wrong. code is