c++ - One class with a vector data member -
i define class vector data member. class looks follows class a{ ... private: std::vector<int> v1; ... }; if use operator new allocate memory class a, program ok. however, if memory pre-allocated memory , cast pointer type a*, program crash. a* = new a; a* b = (a*)pre_allocated_memory_pointer. i need 1 vector variable size , hope memory 1 pre-allocated memory. have idea problem? an std::vector object requires initialization, cannot allocate memory , pretend you've got vector . if need control memory solution defining operator::new class. struct myclass { std::vector<int> x; ... other stuff ... void *operator new(size_t sz) { ... somewhere sz bytes , return pointer them ... } void operator delete(void *p) { ... memory free ... } }; another option instead specify allocate object using placement new: struct myclass { std::vector<int> x; ... other stuff ... }; void foo() { void *...
