1+2+3+4......+n=sum
import java.util.Scanner;
public class xun {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
int i,n,sum=0;
Scanner ln=new Scanner(System.in);
System.out.println("规定当输入0时,停止运行");
do{
System.out.println("输入前n项和中n的大小,按enter键以确认");
n=ln.nextInt();
for(i=1;i<=n;i++)
{
sum+=i;
}
System.out.println("sum="+sum);
sum=0;
}while(n!=0);
System.out.println("运行结束");
}
}
answer: