Added new sample programs to the eclipse plugins for C++ and Java.

Modified examples.xml for the corresponding added programs.

Change-Id: I3d86c570f446ec8cf3013c58dd94215f2907bbb1

eclipse-plugins/edu.wpi.first.wpilib.plugins.cpp/resources/templates/examples/PotentiometerPID/src/Robot.cpp

@@ -0,0 +1,85 @@
+#include "WPILib.h"
+
+/**
+ *  This is a sample program to demonstrate how to use a soft potentiometer and a PID
+ *  Controller to reach and maintain position setpoints on an elevator mechanism.
+ *
+ * WARNING: While it may look like a good choice to use for your code if you're inexperienced,
+ * don't. Unless you know what you are doing, complex code will be much more difficult under
+ * this system. Use IterativeRobot or Command-Based instead if you're new.
+ */
+
+class Robot: public SampleRobot {
+	const int potChannel = 1; //analog input pin
+	const int motorChannel = 7; //PWM channel
+	const int joystickChannel = 0; //usb number in DriverStation
+	const int buttonNumber = 4; //button on joystick
+
+	const double setPoints[3] = { 1.0, 2.6, 4.3 }; //bottom, middle, and top elevator setpoints
+
+	//proportional, integral, and derivative speed constants; motor inverted
+	//DANGER: when tuning PID constants, high/inappropriate values for pGain, iGain,
+	//and dGain may cause dangerous, uncontrollable, or undesired behavior!
+	const double pGain = -5.0, iGain = -0.02, dGain = -2.0; //these may need to be positive for a non-inverted motor
+
+	PIDController *pidController;
+	AnalogInput *potentiometer;
+	Victor *elevatorMotor;
+	Joystick *joystick;
+
+public:
+	Robot() :
+		SampleRobot()
+	{
+		//make objects for potentiometer, the elevator motor controller, and the joystick
+		potentiometer = new AnalogInput(potChannel);
+		elevatorMotor = new Victor(motorChannel);
+		joystick = new Joystick(joystickChannel);
+
+		//potentiometer (AnalogInput) and elevatorMotor (Victor) can be used as a
+		//PIDSource and PIDOutput respectively
+		pidController = new PIDController(pGain, iGain, dGain, potentiometer,
+				elevatorMotor);
+	}
+
+	/**
+	 * Runs during autonomous.
+	 */
+	void Autonomous() {
+
+	}
+
+	/**
+	 *  Uses a PIDController and an array of setpoints to switch and maintain elevator positions.
+     *  The elevator setpoint is selected by a joystick button.
+	 */
+	void OperatorControl() {
+		pidController->SetInputRange(0, 5); //0 to 5V
+		pidController->SetSetpoint(setPoints[0]); //set to first setpoint
+
+		int index = 0;
+		bool currentValue;
+		bool previousValue = false;
+
+		while (IsOperatorControl() && IsEnabled()) {
+			pidController->Enable(); //begin PID control
+
+			//when the button is pressed once, the selected elevator setpoint is incremented
+			currentValue = joystick->GetRawButton(buttonNumber);
+			if (currentValue && !previousValue) {
+				pidController->SetSetpoint(setPoints[index]);
+				index = (index + 1) % (sizeof(setPoints)/8); //index of elevator setpoint wraps around
+			}
+			previousValue = currentValue;
+		}
+	}
+
+	/**
+	 * Runs during test mode.
+	 */
+	void Test() {
+
+	}
+};
+
+START_ROBOT_CLASS(Robot);