commit 17ca504f60fb55472fea85925468b24cfc43b5b8
Author: Gerardo Marx <gmarx_cc@itmorelia.edu.mx>
Date:   Mon Apr 20 03:04:21 2020 +0000

    Class LED for usrLeds

diff --git a/MLed.cpp b/MLed.cpp
new file mode 100644
index 0000000..644866b
--- /dev/null
+++ b/MLed.cpp
@@ -0,0 +1,97 @@
+/*OOP in C++ example for LEDs */
+#include<iostream>
+#include<fstream>
+#include<string>
+#include<sstream>
+using namespace std;
+
+#define LED_PATH "/sys/class/leds/beaglebone:green:usr"
+
+class LED{
+private:
+  string path;
+  int number;
+  virtual void writeLED(string filename, string value);
+  virtual void removeTrigger();
+public:
+  LED(int number);
+  virtual void turnOn();
+  virtual void turnOff();
+  virtual void flash(string delayms);
+  virtual void outputState();
+  virtual ~LED();
+};
+
+LED::LED(int number){
+  this->number = number;
+  ostringstream s;
+  s << LED_PATH << number; // LED number to the Path
+  path = string(s.str()); // convert to string
+}
+
+void LED::writeLED(string filename, string value){
+  ofstream fs;
+  fs.open((path + filename).c_str());
+  fs << value;
+  fs.close();
+}
+
+void LED::removeTrigger(){
+  writeLED("/trigger", "none");
+}
+
+void LED::turnOn(){
+  cout << "Turning LED" << number << "on" << endl;
+  removeTrigger();
+  writeLED("/brightness", "1");
+}
+
+void LED::turnOff(){
+  cout << "Turning LED" << number << "off" << endl;
+  removeTrigger();
+  writeLED("/brightness", "0");
+}
+
+void LED::flash(string delayms ="50"){
+  cout << "Making LED" << number << "flash" << endl;
+  writeLED("/trigger", "timer");
+  writeLED("/delay_on", delayms);
+  writeLED("/delay_off", delayms);
+}
+
+void LED::outputState(){
+  ifstream fs;
+  fs.open((path + "/trigger").c_str());
+  string line;
+  while(getline(fs,line)) cout << line <<endl;
+  fs.close();
+}
+
+LED::~LED(){
+  cout << "!!Destroying the LED with path: " << path << endl;
+}
+
+int main(int argc, char* argv[]){
+  if(argc!=2){
+    cout << "The usage is main <command>" << endl;
+    cout << "<command> is on, off flash or status" << endl;
+    cout << "e.g. main on" << endl;
+  }
+  cout << "Starting program ..." << endl;
+  string cmd(argv[1]);
+  LED leds[4] = {LED(0), LED(1), LED(2), LED(3)};
+  for(int i=0; i<=3; i++){
+    if(cmd=="on")
+      leds[i].turnOn();
+    else if(cmd=="off")
+      leds[i].turnOff();
+    else if(cmd=="flash")
+      leds[i].flash("100");
+    else if(cmd=="status")
+      leds[i].outputState();
+    else
+      cout << "invalid command, please type main" << endl;
+  }
+  cout << "Program done, Thanks." << endl;
+  return 0;
+}