Programming of Line Detector Robots using Arduino

int mot1=9;
int mot2=6;
int mot3=5;
int mot4=3;

int left=13;
int right=12;

int Left=0;
int Right=0;

void LEFT (void);
void RIGHT (void);
void STOP (void);

void setup()
{
  pinMode(mot1,OUTPUT);
  pinMode(mot2,OUTPUT);
  pinMode(mot3,OUTPUT);
  pinMode(mot4,OUTPUT);

  pinMode(left,INPUT);
  pinMode(right,INPUT);

  digitalWrite(left,HIGH);
  digitalWrite(right,HIGH);


}

void loop()
{

analogWrite(mot1,255);
analogWrite(mot2,0);
analogWrite(mot3,255);
analogWrite(mot4,0);

while(1)
{
  Left=digitalRead(left);
  Right=digitalRead(right);

  if((Left==0 && Right==1)==1)
  LEFT();
  else if((Right==0 && Left==1)==1)
  RIGHT();
}
}

void LEFT (void)
{
   analogWrite(mot3,0);
   analogWrite(mot4,30);
 
 
   while(Left==0)
   {
    Left=digitalRead(left);
    Right=digitalRead(right);
    if(Right==0)
    {
      int lprev=Left;
      int rprev=Right;
      STOP();
      while(((lprev==Left)&&(rprev==Right))==1)
      {
         Left=digitalRead(left);
         Right=digitalRead(right);
      }
    }
    analogWrite(mot1,255);
    analogWrite(mot2,0);
   }
   analogWrite(mot3,255);
   analogWrite(mot4,0);
}

void RIGHT (void)
{
   analogWrite(mot1,0);
   analogWrite(mot2,30);

   while(Right==0)
   {
    Left=digitalRead(left);
    Right=digitalRead(right);
    if(Left==0)
    {
      int lprev=Left;
      int rprev=Right;
     STOP();
      while(((lprev==Left)&&(rprev==Right))==1)
      {
         Left=digitalRead(left);
         Right=digitalRead(right);
      }
    }
    analogWrite(mot3,255);
    analogWrite(mot4,0);
    }
   analogWrite(mot1,255);
   analogWrite(mot2,0);
}
void STOP (void)
{
analogWrite(mot1,0);
analogWrite(mot2,0);
analogWrite(mot3,0);
analogWrite(mot4,0);

}