Add samples for "Why C++ programmers stopped using NULL?"

Author: bblanchon

Null/Null.ino

@@ -0,0 +1,47 @@
+// C++ for Arduino
+// Why C++ programmers stopped using NULL?
+//
+// Read the article:
+// https://cpp4arduino.com/2018/10/26/why-cpp-programmers-stopped-using-null.html
+
+template <typename T>
+void printValue(T value);
+
+template <>
+void printValue<int>(int value) {
+  Serial.print("Integer: ");
+  Serial.println(value, DEC);
+}
+
+template <>
+void printValue<void *>(void *value) {
+  Serial.print("Pointer: 0x");
+  Serial.println((intptr_t)value, HEX);
+}
+
+void setup() {
+  Serial.begin(9600);
+  while (!Serial)
+    continue;
+
+  const char *color = NULL;
+  String colorStr1(color);
+  String colorStr2(NULL);
+
+  if (colorStr1 == colorStr2) {
+    Serial.println("colorStr1 == colorStr2");
+  } else {
+    Serial.println("colorStr1 != colorStr2");
+  }
+
+  Serial.print("colorStr1 = ");
+  Serial.println(colorStr1);
+  Serial.print("colorStr2 = ");
+  Serial.println(colorStr2);
+
+  printValue(42);
+  printValue((void *)0x101);
+  printValue(NULL);
+}
+
+void loop() {}

Null/README.md

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+# Why C++ programmers stopped using NULL?
+
+Read the article on [cpp4arduino.com](https://cpp4arduino.com/2018/10/26/why-cpp-programmers-stopped-using-null.html)