boolean variable

i came across code lately internet. find hard understand. can please explain me each line of code.

code: [select]

boolean checkbutton()
{
  char state = digitalread(2);
  if(state == high && pressed == false)
  {
    pressed = true;
    return false;
  }
  if(state == low && pressed == true)
  {
    mode++;
    if(mode > 2)
    mode = 0;
    clearleds();
    pressed = false;
    return true;
  }
  return false;
}

code: [select]


boolean checkbutton()    //declares function returns boolean , takes no arguments when called
{
  char state = digitalread(2);  //reads pin 2 , puts result in newly declared named state of type char (a byte)
  if (state == high && pressed == false) //if value of state variable high , value of pressed boolean variable (presumably declared , givean value global variable) false
  {
    pressed = true;  //set boolean variable true
    return false;  //return value of false program called function
  }
  if (state == low && pressed == true) //if value of state variable low , value of pressed boolean variable (presumably declared , given value global variable) true
  {
    mode++;    //increment mode variable (presumably global variable)
    if (mode > 2) //if mode greater 2
      mode = 0;    //set mode 2
    clearleds();  //either way call clearleds() function then
    pressed = false;  //set pressed true then
    return true;      //return value of true program called function
  }
  return false;  //otherwise return value of false program called function
}


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