how to allocate on heap in c 2b 2b

1//placement new in c++
2char *buf  = new char[sizeof(string)]; // pre-allocated buffer
3string *p = new (buf) string("hi");    // placement new
4string *q = new string("hi");          // ordinary heap allocation
5/*Standard C++ also supports placement new operator, which constructs 
6an object on a pre-allocated buffer. This is useful when building a 
7memory pool, a garbage collector or simply when performance and exception 
8safety are paramount (there's no danger of allocation failure since the memory
9has already been allocated, and constructing an object on a pre-allocated
10buffer takes less time):
11*/

1#include <iostream>
2#include <string>
3
4using String = std::string;
5class Entity
6{
7private:
8	String m_Name;
9public:
10	Entity() : m_Name("Unknown") {}
11	Entity(const String& name) : m_Name(name) {}
12	const String& GetName() const {
13		return m_Name;
14	};
15};
16int main() {
17  // new keyword is used to allocate memory on heap
18	int* b = new int; // new keyword will call the c function malloc which will allocate on heap  memory = data and return a ptr to that plaock of memory
19	int* c = new int[50];
20	Entity* e1 = new Entity;//new keyword Not allocating only memory but also calling the constructor
21	Entity* e = new Entity[50];
22	//usually calling new will  call underlined c function malloc
23	//malloc(50); 
24	Entity* alloc = (Entity*)malloc(sizeof(Entity));//will not call constructor only  allocate memory = memory of entity
25	delete e;//calls a c function free
26	Entity* e3 = new(c) Entity();//Placement New
27}
28