I bought a 12VDC 1A wall wart and when I plug it into my Arduino I dont get any power.

What am I doing wrong????

int photocellPin = 0;    //cell and 10k pulldown are connedted to A0
int photocellReading;    // analog reading from the analog resistor divider

void setup(void) {
  // We'll send debugging information via the Serial Monitor
  Serial.begin(9600);
}

void loop(void)  {
   photocellReading = analogRead(photocellPin)

  Serial.print("Analog reading = ") ,
  Serial.print(photocellReading) ;      //the raw analog reading

  // We'll have a few threshholds, qualitatively determined
  if  (photocellReading < 10) {
  Serial.println(" - Dark");
  } else if (photocellReading < 400)  {
  Serial.println(" - Dim") ;
  } else if (photocellReading < 600)  {
  Serial.println(" - Light") ;
  } else if (photocellReading < 800   {
  Serial.println(" - Bright") ;
  } else {
  Serial.println(" - Very bright") ;
  }
  delay(1000) ;
}

Errors
ldr_test.cpp: In function 'void loop()':
ldr_test:11: error: expected `;' before 'Serial'
ldr_test:21: error: expected `)' before '{' token

I am new to hardware of electronics. I have an Ardunio 2 module relay switch and a Arduino Uno USB Microcontroller Rev 3. I will have about a clear PVC pipes attached with automatic shut off valve and a contamination sensor. For the contamination sensor I will use a LDR with a LED light that will shine on it. When it senses contamination, I want the relay switch to cut off the valve and stop water flow. Im still in the beginning stages of the project I just need to get the basics down.

Can anyone help???
 THanks