Fixed EEPROM examples to remove any doubt for beginners.

Fixes arduino/Arduino#5488
Fixes arduino#3841

Author: Chris--A

hardware/arduino/avr/libraries/EEPROM/examples/eeprom_clear/eeprom_clear.ino

@@ -11,9 +11,10 @@
 #include <EEPROM.h>
 
 void setup() {
+
   // initialize the LED pin as an output.
   pinMode(13, OUTPUT);
-  
+
   /***
     Iterate through each byte of the EEPROM storage.
 
@@ -27,7 +28,14 @@ void setup() {
   ***/
 
   for (int i = 0 ; i < EEPROM.length() ; i++) {
-    EEPROM.write(i, 0);
+
+    /*
+        Use the update method to prevent un-necessary wear on already cleared cells.
+        The update method checks to see if the current cell is different before writing.
+        You could easily replace this with EEPROM.write(i, 0); or even EEPROM.put(i, 0);
+    */
+
+    EEPROM.update(i, 0);
   }
 
   // turn the LED on when we're done

hardware/arduino/avr/libraries/EEPROM/examples/eeprom_get/eeprom_get.ino

@@ -17,10 +17,12 @@
 
 #include <EEPROM.h>
 
+//EEPROM address to start reading from. This does not need to be global, but in this example, it is shared between two different functions.
+int eeAddress = 0;
+
 void setup() {
 
   float f = 0.00f;   //Variable to store data read from EEPROM.
-  int eeAddress = 0; //EEPROM address to start reading from
 
   Serial.begin(9600);
   while (!Serial) {
@@ -52,7 +54,7 @@ struct MyObject {
 };
 
 void secondTest() {
-  int eeAddress = sizeof(float); //Move address to the next byte after float 'f'.
+  eeAddress += sizeof(float); //Move address to the next byte after float 'f'.
 
   MyObject customVar; //Variable to store custom object read from EEPROM.
   EEPROM.get(eeAddress, customVar);