不再更新，杭电ACM的题转到csdn博客
import java.util.*;
public class Main {
public static void main(String[] args) {
Scanner scan=new Scanner(System.in);
int a;
while(scan.hasNextInt()){
a=scan.nextInt();
System.out.println(sum(a));
System.out.println();
}
}
static int sum(int a){
int sum=0;
for(int i=1;i<=a;i++){
sum+=i;
}
return sum;
}
}
