new function c++ code example

Example 1: How to make a function in C++

//first lets create a function
/*void is for starting something, anything after void will be the name of your
function which will be followed by () */
void yourFunction() {
//your code will be here, anything here will be the code in the yourFunction
  cout << "Functions"
}
//now we have to go to our main function, the only function the compiler reads
int main() {
  myFunction(); //you call the function, the code we put in it earlier will be executed
  return 0;
}

Example 2: function in c++

#include <iostream>

using namespace std;

void function(){
    cout << "I am a function!" << endl;
}

int main()
{
    function();

    return 0;
}

Example 3: new in c++

#include <iostream>
#include <string>

using String = std::string;
class Entity
{
private:
	String m_Name;
public:
	Entity() : m_Name("Unknown") {}
	Entity(const String& name) : m_Name(name) {}
	const String& GetName() const {
		return m_Name;
	};
};
int main() {
  // new keyword is used to allocate memory on heap
	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
	int* c = new int[50];
	Entity* e1 = new Entity;//new keyword Not allocating only memory but also calling the constructor
	Entity* e = new Entity[50];
	//usually calling new will  call underlined c function malloc
	//malloc(50); 
	Entity* alloc = (Entity*)malloc(sizeof(Entity));//will not call constructor only  allocate memory = memory of entity
	delete e;//calls a c function free
	Entity* e3 = new(c) Entity();//Placement New

Example 4: new in c++

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