Vector of Smart Pointers (revised)

The previous example doesn't really show the polymorphism. This example shows the coolness of C++ (version 14):

#include <iostream>
#include <vector>
#include <memory>


// Require C++ version 14 to compile!

class Base
{
public:
    Base(Base & other);
    Base(Base *);
    Base(char const * const tag, char const * const desc) : m_tag(tag), m_desc(desc) {}
    ~Base() = default;

    void print();
    virtual void Process(); 

public:
    std::string m_tag = "";
    std::string m_desc = "";
};



Base::Base(Base & rhs)
{
    m_tag = rhs.m_tag;
    m_desc = rhs.m_desc;
}


Base::Base(Base *pOther)
{
    m_tag = pOther->m_tag;
    m_desc = pOther->m_desc;
}


void Base::print()
{
    std::cout << __FUNCTION__ << "(" << this << "): Base::m_tag = " << m_tag << std::endl 
              << "                  Base::m_desc = " << m_desc << std::endl;
}


void Base::Process()
{
    std::cout << __PRETTY_FUNCTION__ << std::endl;
}



template <class CNAME>
Base* createClass(char const *const tag, char const * const desc)
{
    CNAME * pObj  = new CNAME(tag,desc);

    std::cout << "Inside " << __FUNCTION__  << "(): ";
    pObj->Process();
    return dynamic_cast<Base*>(pObj);
}


template <class CNAME>
std::unique_ptr<Base> createUniqueClass(char const *const tag, char const *const desc)
{
    std::unique_ptr<Base> obj(createClass<CNAME>(tag, desc));
    return obj;
}



class KelasA : public Base
{
public:

    KelasA(char const * const tag, char const * const desc) : Base(tag, desc) {}
    void Process() override;
};


void KelasA::Process()
{
    std::cout << __PRETTY_FUNCTION__ << std::endl;
}


class KelasB : public Base
{
public:
    KelasB(char const * const tag, char const * const desc) : Base("B", desc) {}
    void Process() override;
};



void KelasB::Process()
{
    std::cout << __PRETTY_FUNCTION__ << std::endl;
}




int main()
{
    std::vector<std::unique_ptr<Base>> vb;

    vb.push_back(createUniqueClass<KelasA>("A", "Kelase A-1"));

    vb.push_back(createUniqueClass<KelasB>("B", "Kelase B-1"));

    //for(auto v = vb.begin(); v != vb.end(); v++)a
    for(auto & v : vb)
    {
        v->Process();
        v->print();
    }

    return 0;
}

Vector of Smart Pointers

#include <iostream>
#include <vector>
#include <memory>


// Require C++ version 14 to compile!

class Base
{
public:
    Base(Base & other);
    Base(Base *);
    Base(char const * const tag, char const * const desc) : m_tag(tag), m_desc(desc) {}

    void print();

public:
    std::string m_tag = "";
    std::string m_desc = "";
};



Base::Base(Base & rhs)
{
    m_tag = rhs.m_tag;
    m_desc = rhs.m_desc;
}


Base::Base(Base *pOther)
{
    m_tag = pOther->m_tag;
    m_desc = pOther->m_desc;
}


void Base::print()
{
    std::cout << __FUNCTION__ << "(" << this << "): Base::m_tag = " << m_tag << std::endl 
              << "                  Base::m_desc = " << m_desc << std::endl;
}


template <class CNAME>
Base * createClass(char const *const tag, char const * const desc)
{
    CNAME *pObj = new CNAME(tag,desc);

    Base *pBase = dynamic_cast<Base*>(pObj);

    return pBase;
}




class KelasA : public Base
{
public:

    KelasA(char const * const tag, char const * const desc) : Base(tag, desc) {}
    void FuncA() {}
};

class KelasB : public Base
{
public:
    KelasB(char const * const tag, char const * const desc) : Base("B", desc) {}
    void FuncA() {}
};


int main()
{
    std::vector<std::unique_ptr<Base>> vb;

    std::unique_ptr<Base> p;
    p = std::make_unique<Base>((createClass<KelasA>("A", "Kelas A-1")));
    vb.push_back(std::move(p));
    p = std::make_unique<Base>((createClass<KelasB>("B", "Kelas B-1")));
    vb.push_back(std::move(p));

    for(auto v = vb.begin(); v != vb.end(); v++)
    {
        (*v)->print();
    }

    return 0;
}

Stream of Prime Numbers

Create an endless stream of prime numbers - a bit like IntStream.of(2,3,5,7,11,13,17), but infinite. The stream must be able to produce a million primes in a few seconds.

ESP8266 vs ESP32

Specifications	ESP8266	ESP32
MCU	Xtensa Single-core 32-bit L106	Xtensa Dual-Core 32-bit LX6 with 600 DMIPS
802.11 b/g/n Wi-Fi	Yes, HT20	Yes, HT40
WiFi Security	?	WEP, WPA/WPA2 PSK/Enterprise
Hardware Accelerated Encryption	?	AES/SHA2/Elliptical Curve Cryptography/RSA-4096
Bluetooth	None	dual-mode: Bluetooth 4.2 BLE or classi
Typical Frequency	80 MHz	240 MHz
SRAM	160 KB	520 KB
Flash	SPI Flash, up to 16 MB	SPI Flash, up to 16 MB, memory mapped to CPU code space.
GPIO	17	36
Hardware/Software PWM	None/8 channels	1/16 channels
SPI/I2S/I2C/UART	2/1/2/2	3/2/2/3
ADC	10 bit	12-bit, 18 channels
DAC	None	2
CAN	None	?
Ethernet MAC Interface	None	1
Touch Sensor	None	Yes
Temperature Sensor	None	yes
Working Temperature	-40 C - 125 C	-40 C - 125 C
Operating Voltage	?	2.3V to 3.6V C
Power Consumption	77 μA	5 μA power consumption in Deep-sleep

Reference: http://espressif.com/en/products/hardware/esp32/overview

My protoboard

ZigBee for IoT

The ZigBee and Z-Wave short-range wireless technologies are used for remote monitoring and control. However, their specifications and applications are different. Both technologies are ideal for home-area networks (HANs), which is becoming an in.

Differences between ZigBee and Z-Wave:

Technology	Frequency	Modulation	Data Rate	Range	Applications
ZigBee	902 to 928 MHz (Americas and Australia)2.4 - 2.483 GHz (ISM)	BPSK (900 MHz band) or OQPSK (2.4 GHz band)	250 kbps	10 m	Home Automation, Smart Grid, Remote control
Z-Wave	908.42 MHz	GFSK	9.6/40 kbps	30 m	Home Automation, security

ZigBee

It is ratified in the IEEE’s 802.15.4 personal-area network (PAN) radio standard. ZigBee is an open wireless standard from the ZigBee Alliance. The IEEE 802.15.4 standard provides layer 1 (physical layer, or PHY) and layer 2 (media access controller, or MAC) of the network, while the ZigBee stack software provides the network and application layers.

The Zigbee protocol is designed to communicate data through hostile RF environments that are common in commercial and industrial applications.

Zigbee protocol features include:

• Support for multiple network topologies such as point-to-point,
• point-to-multipoint and mesh networks
• Low duty cycle – provides long battery life
• Low latency
• Direct Sequence Spread Spectrum (DSSS)
• Up to 65,000 nodes per network
• 128-bit AES encryption for secure data connections
• Collision avoidance, retries, and acknowledgments (CSMA/CA)

ZigBee Physical Layer

ZigBee PHY operates in various bands, but the most common one is in the 2.4 GHz band. It uses offset quadrature phase-shift keying (OQPSK) that transmits two bits per symbol. In 900 MHz band, it uses BPSK for modulation.  The radio uses DSSS for digital streaming.

There are three (3) kind of devices in ZigBee:

1. ZigBee Coordinator (ZR)
2. ZigBee Router (ZR)
3. ZigBee End Device (ZED)