arduino+processing=proplem

Projects Interfacing w/ Software on the Computer
7

today before I tried your advice I did something that I thought that can solve the promblem and it Succeeded this is the new and working codes
arduino

int ledpin=9;
void setup() {
pinMode(ledpin,OUTPUT);
Serial.begin(9600);
}

void loop() {
  int sensorValue = analogRead(A0);
if(sensorValue>600){
  analogWrite(ledpin,0);
  Serial.println('0');
}
if((sensorValue<490)&&(sensorValue>350)){
  analogWrite(ledpin,50);
  Serial.println("1");
}
if(sensorValue<350)
{analogWrite(ledpin,255);
Serial.println('1');
}

}

processing

import processing.serial.*;
Serial port;
int brightness;
String bool="";
int index=0;
PFont font;
void setup()

{
  size(500,220);
port=new Serial(this,"COM4",9600);
font = loadFont("AgencyFB-Bold-200.vlw");
textFont(font,200);
}
  void draw()
  {
  background(brightness,brightness,brightness);
  fill(75,150,196);
  text(bool,80,175);
}
void serialEvent (Serial port)
{index=port.read();
  if(index=='1')
{
    
  bool="dark";
brightness=0;
}
if(index=='0')
{
  bool="light";
  brightness=255;
}}