Shared Pointer Example 1

shared_ptr_e1.cpp

#include <iostream>
#include <memory>

using namespace std;

class SomeBigObject{
public:
    float data[1000];
    
    void something() {
        // just something
    }

    void someOtherThing(){
        // just some other thing
    }
};

void SomeFunction(shared_ptr<SomeBigObject>& p){
    shared_ptr<SomeBigObject> p2 = make_shared<SomeBigObject>(); // allocate memory
    p = p2; // copy p2 into the pointer passed (ref count = 2)
    
    // p and p2 point at the same object
} // the memory at which p2 points will not be freed here, 
 //  but the ref count will decrement and be 1


int main(){
    shared_ptr<SomeBigObject> p1;

    SomeFunction(p1);
    // the memory allocated by p2 will be freed when the main function ends

    p1->something();
    p1->someOtherThing();

    return 0;
    // p1 will go out of scope, ref count will go 0
    // and memory will be freed
}