Smart Pointer unique_ptr, shared_ptr, weak_ptr

 #include <iostream>

#include <fstream>

#include<cstdio>

#include<stdio.h>

#include <string>

#include "Header.h";

#include <stdlib.h>

#include <time.h>

#include <stdlib.h>

#include<iomanip>

using namespace std;

class Demo {

public:

    int a, b;

    Demo(int a, int b) {

        this->a = a;

        this->b = b;

    }

    void Display() {

        cout << "a=" << a << "b=" << b;

    }

    ~Demo() {

        cout << "\nDistructor\n";

    }

};

/*

1) int 2 sum  

2) double 2 sum

3) string concat name

*/

int Sum(int a, int b) {

    return (a + b);

}

double Sum(double a, double b) {

    return (a + b);

}

//char* Sum(char* a, char* b) {

//

//

//  return strcat(a, b);//(a+b)

//}

//Enter

int main() {

    char a='a';

    char b='c';

   

   

    cout << "Sum=" << Sum(12, 90)<<endl;

    cout << "Sum=" << Sum(12.0, 90.88) << endl;

    //cout << "Sum=" << Sum(a,b) << endl;

   

    /*unique_ptr<Demo> ptr1 = make_unique<Demo>(12, 8);

    cout << "ptr1\n";

    ptr1->Display();

    unique_ptr<Demo> ptr2 = move(ptr1);

    cout << "\nptr2\n";

    ptr2->Display();

    cout << "ptr1\n";

    ptr1->Display();*/  //error nullptr

    //shared_ptr<Demo> ptr1 = make_shared<Demo>(12, 8);

    //cout << "ptr1\n";

    //ptr1->Display();

    //shared_ptr<Demo> ptr2 = ptr1;

    //cout << "\nptr2\n";

    //ptr2->Display();

    //cout << "ptr1\n";

    //ptr1->Display();  //

    shared_ptr<Demo> ptr1 = make_shared<Demo>(12, 8);  // ptr2 pt3  

    ptr1->Display();

    weak_ptr<Demo> ptr2 = ptr1;

    //====memory deallocate

    ptr1.reset(); //delete

    if (auto r = ptr2.lock()) {

        cout << "Object Live";

    }

    else {

        cout << "Object Delete";

    }

    return 0;

}