Arduino edge avoiding robot

#include <AFMotor.h>   

AF_DCMotor MotorL(4);  // Motor for drive Left on M4
AF_DCMotor MotorR(3);  // Motor for drive Right on M3

//ultrasonic setup:
 const int trigPin = A4; // trig pin connected to Arduino's pin A4
 const int echoPin = A5; // echo pin connected to Arduino's pin A5

// defines variables
long duration;
int distanceCm=0;

void setup() {
  Serial.begin(115200);      // set up Serial library at 115200 bps
  Serial.println("*robot Edge Avoidance Mod*");
  pinMode(trigPin, OUTPUT);  // Sets the trigPin as an Output
  pinMode(echoPin, INPUT);   // Sets the echoPin as an Input

  // Set the speed to start, from 0 (off) to 255 (max speed)
  // sometimes the motors don't have the same speed, so use these values tomake your robot move straight
  MotorL.setSpeed(100);
  MotorR.setSpeed(100);
  // turn on motor
  MotorL.run(RELEASE);
  MotorR.run(RELEASE);
}

// main program loop
void loop() {
 distanceCm=getDistance(); // variable to store the distance measured by the sensor
   
 Serial.println(distanceCm); // print the distance that was measured

  //if the distance is more than 10cm, robot will go backward for 1 second, and turn right for 1 second
  if(distanceCm > 7){
    MotorL.run(BACKWARD);
    MotorR.run(BACKWARD);
    delay(500);
    MotorL.run(FORWARD);
    MotorR.run(BACKWARD);
    delay(500);
  } else {
    MotorL.run(FORWARD); //otherwise it will continue forward
    MotorR.run(FORWARD);
  }
}



//RETURNS THE DISTANCE MEASURED BY THE HC-SR04 DISTANCE SENSOR
int getDistance() {
  int echoTime;                   //variable to store the time it takes for a ping to bounce off an object
  int calcualtedDistance;         //variable to store the distance calculated from the echo time
  
  //send out an ultrasonic pulse that's 10ms long
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10); 
  digitalWrite(trigPin, LOW);

  echoTime = pulseIn(echoPin, HIGH);      //use the pulsein command to see how long it takes for the
                                          //pulse to bounce back to the sensor

  calcualtedDistance = echoTime / 58.26;  //calculate the distance of the object that reflected the pulse (half the bounce time multiplied by the speed of sound)
  return calcualtedDistance;              //send back the distance that was calculated
}