Loop the data already received on the serial monitor

Projects General Guidance
10

#define ENA 5
#define ENB 6
#define IN1 7
#define IN2 8
#define IN3 9
#define IN4 11
#define LED 13

String readString;
unsigned char carSpeed = 250;
bool state = LOW;
char getstr;

void forward(){
digitalWrite(ENA,HIGH);
digitalWrite(ENB,HIGH);
digitalWrite(IN1,HIGH);
digitalWrite(IN2,LOW);
digitalWrite(IN3,LOW);
digitalWrite(IN4,HIGH);
Serial.println("Forward");
}

void back(){
digitalWrite(ENA,HIGH);
digitalWrite(ENB,HIGH);
digitalWrite(IN1,LOW);
digitalWrite(IN2,HIGH);
digitalWrite(IN3,HIGH);
digitalWrite(IN4,LOW);
Serial.println("Back");
}

void left(){
analogWrite(ENA,carSpeed);
analogWrite(ENB,carSpeed);
digitalWrite(IN1,LOW);
digitalWrite(IN2,HIGH);
digitalWrite(IN3,LOW);
digitalWrite(IN4,HIGH);
Serial.println("Left");
}

void right(){
analogWrite(ENA,carSpeed);
analogWrite(ENB,carSpeed);
digitalWrite(IN1,HIGH);
digitalWrite(IN2,LOW);
digitalWrite(IN3,HIGH);
digitalWrite(IN4,LOW);
Serial.println("Right");
}

void stop(){
digitalWrite(ENA,LOW);
digitalWrite(ENB,LOW);
Serial.println("Stop!");
}

void stateChange(){
state = !state;
digitalWrite(LED, state);
Serial.println("Light");
}

void record(){
Serial.flush();
}

void pauserec(){

}

void playdata(){

}

void setup() {
Serial.begin(9600);
pinMode(LED, OUTPUT);
pinMode(IN1,OUTPUT);
pinMode(IN2,OUTPUT);
pinMode(IN3,OUTPUT);
pinMode(IN4,OUTPUT);
pinMode(ENA,OUTPUT);
pinMode(ENB,OUTPUT);
stop();
}

void loop()
{
getstr = Serial.read();
switch(getstr)
{
case 'f': forward(); break;
case 'b': back(); break;
case 'l': left(); break;
case 'r': right(); break;
case 's': stop(); break;
case 'a': stateChange(); break;
case 'rec': record(); break;
case 'pauserec': pauserec(); break;
case 'play': playdata(); break;
default: break;
}
}