求一个C++的稀疏矩阵类，要求能实现加法，减法和乘法，正常输出。不是结构体

private void waitConn()
{
ConnServer = new UdpClient(1899);
IPEndPoint iep = new IPEndPoint(IPAddress.Any, 1899);
Conn conn = InitConn();
while (true)
{
Thread.Sleep(30);
byte[] bData = ConnServer.Receive(ref iep);
string s = Encoding.Default.GetString(bData, 0, bData.Length);
string s2 =doSomeThing(s);//这个函数很简单，不费时
SendGroup(s2, Group_IPEndPoint);//组播发送出去