急求C++6.0解題，1、編程求1到n中能被3或7整除的數之和。分別用for循環語句和while循環語句完成本題。

#include <iostream>

using namespace std;

int main()

{

int n;

cout<<"enter the lenth of the side:"<<endl;

cin>>n;

for (int a=1;a<=n;a++)

{

for (int b=1;b<=n-a;b++)

{

cout<<" ";

}

for (int c=1;c<=2*a-1;c++)

{

cout<<"*";

}

cout<<endl;

}

for (int A=n-1;A>0;A--)

{

for (int B=1;B<=n-A;B++)

{

cout<<" ";

}

for (int C=1;C<=2*A-1;C++)

{

cout<<"*";

}

cout<<endl;

}

return 0;

}