求求Sn=a+aa+aaa+…+aa…a（n个a）和

例如：1 + 11 + 111 + 1111（n = 4） = ?

#include<iostream>

using namespace std;

int main()
{
    int a, n, sum = 0, num = 0, i = 0;
    cout<<"输入a 和 n :";
    cin>>a>>n;
    while(i < n)
    {
        num = num + a;
        sum = sum + num;
        a = a * 10;
        i++;
    }
    cout<<sum;
    return 0;
}

标签：aa,aaa,cout,int,sum,num,Sn,main
来源： https://blog.csdn.net/KO812605128/article/details/123146100