C++ RAII made simpler by using smart pointers

raii.cpp

/*

# C++ RAII example

Compile with:

```sh
$ g++ -Wall -O3 -g -o raii raii.cpp
```

Valgrind:

```sh
$ valgrind --tool=memcheck --leak-check=full --show-leak-kinds=all --track-origins=yes ./raii
==52320== Memcheck, a memory error detector
==52320== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==52320== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==52320== Command: ./raii
==52320== 
Foo = 10
Bar = 10
Data = 10
==52320== 
==52320== HEAP SUMMARY:
==52320==     in use at exit: 4 bytes in 1 blocks
==52320==   total heap usage: 5 allocs, 4 frees, 73,760 bytes allocated
==52320== 
==52320== 4 bytes in 1 blocks are definitely lost in loss record 1 of 1
==52320==    at 0x483BE63: operator new(unsigned long) (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==52320==    by 0x109193: Foo (raii.cpp:12)
==52320==    by 0x109193: main (raii.cpp:60)
==52320== 
==52320== LEAK SUMMARY:
==52320==    definitely lost: 4 bytes in 1 blocks
==52320==    indirectly lost: 0 bytes in 0 blocks
==52320==      possibly lost: 0 bytes in 0 blocks
==52320==    still reachable: 0 bytes in 0 blocks
==52320==         suppressed: 0 bytes in 0 blocks
==52320== 
==52320== For lists of detected and suppressed errors, rerun with: -s
==52320== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
```

*/

#include <cstdio>
#include <memory>

struct Data {
    int value;
};

class Foo {
public:
	Foo()
	{
		this->my_foo = new Data();
	}

	void set(int v)
	{
		this->my_foo->value = v;
	}

	int get()
	{
		return this->my_foo->value;
	}

protected:
	Data *my_foo;
};

class Bar {
public:
	Bar()
	{
		this->my_bar = std::shared_ptr<Data>(new Data());
	}

	void set(int v)
	{
		this->my_bar->value = v;
	}

	int get()
	{
		return this->my_bar->value;
	}

    std::shared_ptr<Data> get_data()
    {
        return this->my_bar;
    }


protected:
	std::shared_ptr<Data> my_bar;
};

int main( void )
{
	Foo foo;
	foo.set(10);

	printf("Foo = %d\n", foo.get());

	Bar bar;
	bar.set(10);

	printf("Bar = %d\n", bar.get());

    std::shared_ptr<Data> d = bar.get_data();

    printf("Data = %d\n", d->value);

	return 0;
}