sensor data question

Using Arduino Programming Questions
6

i might be adding incorrect values, but heres what i implemented, without any results:

unsigned long now;
unsigned long then = 0;
int prevSensorValue = 5;
const int pingPin = 7;
int bigChange = 5;
unsigned long longTime = 5;


int currSensorValue = analogRead(pingPin);
   if((abs(currSensorValue - prevSensorValue)) > bigChange)
   {
      // a change occurred
      then = millis();

     digitalWrite(led13, HIGH); // Do something with the sensor data
   }

  now = millis();

  if(now - then > longTime)
  {
    digitalWrite(led13, LOW); // It's been a while since a change occurred
  }

  int values = cm;


  //forwrd fade
  outputValue1 = map(values, 25, 40, 0, 255);
  outputValue2 = map(values, 40, 25, 0, 255);
  outputValue3 = map(values, 3, 24, 0, 255);
  outputValue4= map(values, 24, 3, 0, 255);
  // change the analog out value:


  //analogWrite(led1, outputValue1);
  //  analogWrite(ledsignal, outputValue2);

  if(values >= 25 ){

    analogWrite(led1, outputValue1);
    analogWrite(ledsignal, outputValue2);
    digitalWrite(led2, LOW);
  }

  if(values >= 3 && values <= 24)
  {
    analogWrite(led2, outputValue4);
    analogWrite(ledsignal, outputValue3);
digitalWrite(led1, LOW);

  
}}

thanks so much for your help.