# define ml1 10
# define ml2 9
# define mr1 5
# define mr2 3

# define IR1 2
# define IR2 12
# define IR3 13
# define IR4 11
# define IR5 8

int spd1=100,spd2=50;

int a,b,c,d,e;

void setup(){
  pinMode(ml1, OUTPUT);
  pinMode(ml2, OUTPUT);
  pinMode(mr1, OUTPUT);
  pinMode(mr2, OUTPUT);

  pinMode(IR1, INPUT);
  pinMode(IR2, INPUT);
  pinMode(IR3, INPUT);
  pinMode(IR4, INPUT);
  pinMode(IR5, INPUT);
}

void loop(){
  read();
  if((a==0)&&(b==0)&&(c==1)&&(d==0)&&(e==0)){
    straight();
  }

  else if(((a==0)&&(b==1))||(a==1)&&(b==0)){
    left();
  }
  else if((a==1)&&(b==1)){
    s_left();
  }

  else if((a==0)&&(b==0)&&(c==1)&&(d==1)){
    do{
      straight();
    }while(d==0);

    read();
    if(c==0){
      right();
    }
    else{
      straight();
    }
  }
  else if((a==0)&&(b==0)&&(c==0)&&(d==0)&&(e==0)){
    back();
  }
}


void read(){
  a=digitalRead(IR1);
  b=digitalRead(IR2);
  c=digitalRead(IR3);
  d=digitalRead(IR4);
  e=digitalRead(IR5);
}

void left(){
  analogWrite(ml1, spd2);
  analogWrite(ml2, LOW);
  analogWrite(mr1, spd1);
  analogWrite(mr2, LOW);
}
void s_left(){
  analogWrite(ml1, LOW);
  analogWrite(ml2, spd1);
  analogWrite(mr1, spd1);
  analogWrite(mr2, LOW);
}

void right(){
  analogWrite(ml1, spd1);
  analogWrite(ml2, LOW);
  analogWrite(mr1, spd2);
  analogWrite(mr2, LOW);
}
void s_right(){
  analogWrite(ml1, spd1);
  analogWrite(ml2, LOW);
  analogWrite(mr1, LOW);
  analogWrite(mr2, spd1);
}

void back(){
  do{
    left();
  }while((a==0)&&(b==0)&&(c==1)&&(d==0)&&(e==0));
}

void straight(){
  analogWrite(ml1, spd1);
  analogWrite(ml2, LOW);
  analogWrite(mr1, spd1);
  analogWrite(mr2, LOW);
}

void stop(){
  analogWrite(ml1, LOW);
  analogWrite(ml2, LOW);
  analogWrite(mr1, LOW);
  analogWrite(mr2, LOW);  
}