examples: Cleanup C++ examples

Modify the C++ examples to be of same coding standard like C. As a
part of this cleanup, a new LED example is also added.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

examples/c++/pwm.cpp

@@ -0,0 +1,74 @@
+/*
+ * Author: Thomas Ingleby <thomas.c.ingleby@intel.com>
+ * Copyright (c) 2014 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Example usage: Generates PWM at a step rate of 0.01 continuously.
+ *                Press Ctrl+C to exit
+ */
+
+/* standard headers */
+#include <iostream>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+/* mraa headers */
+#include "mraa/common.hpp"
+#include "mraa/pwm.hpp"
+
+#define PWM_PORT 3
+
+volatile sig_atomic_t flag = 1;
+
+void
+sig_handler(int signum)
+{
+    if (signum == SIGINT) {
+        std::cout << "Exiting..." << std::endl;
+        flag = 0;
+    }
+}
+
+int
+main(void)
+{
+    float value = 0.0f;
+
+    signal(SIGINT, sig_handler);
+
+    //! [Interesting]
+    mraa::Pwm pwm(PWM_PORT);
+    std::cout << "Cycling PWM on IO3 (pwm3)" << std::endl;
+    pwm.enable(true);
+
+    while (flag) {
+        value = value + 0.01f;
+        pwm.write(value);
+        usleep(50000);
+        if (value >= 1.0f) {
+            value = 0.0f;
+        }
+    }
+    //! [Interesting]
+
+    return EXIT_SUCCESS;
+}