dynamic memory allocation in c 2b 2b

1int * foo;
2foo = new int [5];

1int length = 69;
2int * numbers = new int[length];
3delete[] numbers;

1int *p = new int; // request memory
2*p = 5; // store value
3
4cout << *p << endl; // Output is 5
5
6delete p; // free up the memory
7
8cout << *p << endl; // Output is 0

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

1char* pvalue  = NULL;         // Pointer initialized with null
2pvalue  = new char[20];       // Request memory for the variable
3

1#include <iostream>
2using namespace std;
3
4int main () {
5   double* pvalue  = NULL; // Pointer initialized with null
6   pvalue  = new double;   // Request memory for the variable
7 
8   *pvalue = 29494.99;     // Store value at allocated address
9   cout << "Value of pvalue : " << *pvalue << endl;
10
11   delete pvalue;         // free up the memory.
12
13   return 0;
14}