char *m_strBuff, *m_strStartPtr, *m_strEndPtr;
size_t m_nBuffSize;
char m_strWorking[BUFF_SIZE];
Where BUFF_SIZE is 201.
You're not using dynamic allocation here, that's cool. But for every one of these objects you create you are consuming 209 bytes of RAM. That's a lot of ram for a string like "Hello World" which as a c-string consumes only 12 bytes. No worries about fragmentation, but even worse you're just going to be out of RAM with just 10 strings.