n是由键盘输入，例如：n=5; 输出S=5+55+555+5555+55555

n是由键盘输入，例如：n=5; 输出 S=5+55+555+5555+55555

import java.util.Scanner;

public class Exercise {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int n,m;
        System.out.println("请输入一个数字:");
        Scanner sc=new Scanner(System.in);
        n=sc.nextInt();
        int sum=n;
        System.out.print("S="+n);
        for(int i=1;i<n;i++){
            m=n;
            int j=1;
            while(j<=i){
                m=m*10+n;
                j++;
            }
            sum+=m;
            System.out.print("+"+m);
        }
        System.out.print("="+sum);
    }

}