Menu
Unlike new and delete operators malloc does not call the constructor when an object is created. In that case how must we create an object so that the constructor will also be called.
637
Unlike new and delete operators malloc does not call the constructor when an object is created. In that case how must we create an object so that the constructor will also be called.
malloc(): It is a C library function that can also be used in C++, while the “new” operator is specific for C++ only. Both malloc() and new are used to allocate the memory dynamically in heap. But “new” does call the constructor of a class whereas “malloc()” does not.
In C, the library function malloc is used to allocate a block of memory on the heap. The program accesses this block of memory via a pointer that malloc returns. When the memory is no longer needed, the pointer is passed to free which deallocates the memory so that it can be used for other purposes.
The malloc() function in C++ allocates a block of uninitialized memory to a pointer. It is defined in the cstdlib header file.
Er...use new? That's kind of the point. You can also call the constructor explicitly, but there's little reason to do it that way
A* a = new A(); delete a; A* a = (A*)malloc(sizeof(A)); new (a) A(); a->~A(); free(a); You can use "placement new" syntax to do that if you really, really need to:
MyClassName* foo = new(pointer) MyClassName();
where pointer is a pointer to an allocated memory location large enough to hold an instance of your object.
39
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
