JOJ1007: Triangles

原题地址http://acm.jlu.edu.cn/joj/showproblem.php?pid=1007

using namespace std;

int main()
{
    int n;
    while(cin>>n && n)
    {
        int f=0,h=0;
        for(int i=1;;++i)
        {
            if(i*(i+1)==2*n)
            {
                f=1;
                h=i;
                break;
            }
            if(i*(i+1)>2*n)
                break;
        }
        if(f)
        {
            cout<<n<<" is a triangular number."<<endl;
            for(int i=1;i<=h;++i)
            {
                for(int j=1;j<=i;++j)
                {
                    cout<<"*";
                }
                    cout<<endl;
            }
        }
        else
            cout<<n<<" is not a triangular number."<<endl;
    }
    return 0;
}