Java 实现从m到n自然数的求和；
package Final;
import java.util.Scanner;
public class _1 {
public static void main (String[] args) {
int m,n,i,sum = 0;
Scanner s=new Scanner(System.in);
m=s.nextInt();
n=s.nextInt();
if(m>n){
System.out.println("Error!");
}else{
for(i=m;i<=n;i++){
sum+=i;
}
System.out.println(sum);
}
}
}