Sum Problem,简单题不能ac

Question

Description
Hey, welcome to HDOJ(Hangzhou Dianzi University Online Judge).

In this problem, your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n.

Input
The input will consist of a series of integers n, one integer per line.

Output
For each case, output SUM(n) in one line, followed by a blank line. You may assume the result will be in the range of 32-bit signed integer.

Sample Input
1
100

Sample Output
1

5050

int main()
{
int n;
while(scanf("%d",&n)==1)
{
int i;
int sum=0;
for(i=1;i<=n;i++)
sum+=i;
printf("%d",sum);
}
return 0;
}

Answer 1

printf("%d",sum);
->
printf("%d\n",sum);