Question

struct Test
{
    int var;
    char *arr;
}

int main()
{
    Test a;
    a.arr = new char[50];
}

The above code would create a dynamic array in the structure but the dynamic array would not be actually memory allocated within the structure, its memory would be allocated somewhere else. I want this array to be allocated in the structure as with the fixed array but I don’t want to use fixed array. Any ideas?
I’ve tried my best to clarify my question, hope you understand.

I want to send this structure through UDP and UDP takes continues memory buffer to send that’s why I want this structure to have continuous memory.

Answer 1

You can not do that as the new memory is from heap/ free store and your a will be allocated on stack….

you can allocate using malloc/new a continous memory block of sizeof Test + your required size and make the pointer arr to point at the end of the Test structure.

If you need it in function scope on stack you can use alloca.

Test *a = (Test*)alloca(sizeof(Test)+yoursize);
a->arr = (char*)a+sizeof(Test)...