Item 34: Understand how to combine C++ and C in the same program.(More Effective C++)

• Make sure the C++ and C compilers produce compatible object files. 
• Declare functions to be used by both languages extern "C". 
• If at all possible, write main in C++. 
• Always use delete with memory from new; always use free with memory from malloc. 
• Limit what you pass between the two languages to data structures that compile under C; the C++ version of structs may contain non-virtual member functions.