Mobile controlled car using Arduino nano

1char t;
2 
3void setup() {
4pinMode(2,OUTPUT);   //left motors forward
5pinMode(3,OUTPUT);   //left motors reverse
6pinMode(4,OUTPUT);   //right motors forward
7pinMode(5,OUTPUT);   //right motors reverse
8pinMode(7,OUTPUT);   //pump
9Serial.begin(9600);
10   digitalWrite(7,HIGH);
11
12}
13 
14void loop() {
15
16if(Serial.available()){
17  t = Serial.read();
18  Serial.println(t);
19}
20 
21if(t == 'F'){            //move  forward(all motors rotate in forward direction)
22  digitalWrite(2,HIGH);
23  digitalWrite(4,HIGH);
24}
25  
26else if(t == 'B'){      //move reverse (all motors rotate in reverse direction)
27  digitalWrite(3,HIGH);
28  digitalWrite(5,HIGH);
29}
30 
31else if(t == 'L'){      //turn right (left side motors rotate in forward direction, right side motors  doesn't rotate)
32  digitalWrite(4,HIGH);
33}
34 
35else if(t == 'R'){      //turn  left (right side motors rotate in forward direction, left side motors doesn't rotate)
36  digitalWrite(2,HIGH);
37}
38else if(t == 'W'){      //turn left (right side  motors rotate in forward direction, left side motors doesn't rotate)
39  digitalWrite(7,0);
40}
41else  if(t == 'w'){      //turn left (right side motors rotate in forward direction, left  side motors doesn't rotate)
42  digitalWrite(7,1);
43}
44
45
46else if(t ==  'S'){      //STOP (all motors stop)
47  digitalWrite(2,LOW);
48  digitalWrite(3,LOW);
49  digitalWrite(4,LOW);
50  digitalWrite(5,LOW);
51}
52}
53