Hey, welcome to HDOJ(Hangzhou Dianzi University Online Judge).
In this problem, your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n.
The input will consist of a series of integers n, one integer per line.
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.
We have carefully selected several similar problems for you:
1013 1010 1006 1020 1007 #include<stdio.h>
int main()
{
int n,i;
double sum;
while(scanf("%ld",&n)!=EOF)
{ sum=0;
for(i=1;i<=n;i++)
sum+=i;
printf("%.0lf\n\n",sum);
}
return 0;
}
