// simulation for https://forum.arduino.cc/t/variable-wont-increment-in-if-statement/964895/2?u=davex

//Fix the typo in the last if statement for proper operation

#include <Ultrasonic.h>
#include <Servo.h>
//#include <ESP8266WiFi.h>
#include <math.h>

#define motorRpin 2
#define motorLpin 3

Servo motorR;
Servo motorL;

//Ultrasonic usFront  (D8, D5);
//Ultrasonic usRight  (D9, D6);
//Ultrasonic usLeft   (D10, D7);

int distFront = 0;
int distRight = 0;
int distLeft  = 0;

int wall = 0;

void setup() {

  Serial.begin(115200);

  motorR.attach(motorRpin);
  motorL.attach(motorLpin);

  motorR.write(90);    //Right Forward  = 0
  motorL.write(90);  //Left Forward = 180

}

void loop() {

//  distFront = usFront.read(CM) * 10;
  //distRight = usRight.read(CM) * 10;
  //distLeft  = usLeft.read(CM) * 10;
  distFront = random(1,100) * 10;
  distRight = random(1,100) * 10;
  distLeft  = random(1,100) * 10;

  //  Serial.println(distFront);
  //  Serial.println(distRight);
  //  Serial.println(distLeft);
  if(wall != 0){
    Serial.print(" ");
   Serial.print(wall);
   Serial.print(" ");
  }
  //delay(100);

  if (wall < 12 && distFront > 150 && distRight > 40 && distLeft > 40) {

    motorR.write(52); //move forward if no obstacles
    motorL.write(180);
    Serial.print("F");

  }

  if (wall < 12 && distFront <= 150) {
    Serial.print("W");

    motorR.write(90); //stop if wall in front
    motorL.write(90);
    delay(500);

    motorR.write(0); //turn left 90 degrees
    motorL.write(0);
    delay(150);

    motorR.write(52);
    motorL.write(180); //go forwards again

    wall++;
    Serial.print(wall);
    distFront = 1000;

    delay(500);

  }

  if (wall < 12 && distFront > 150 && distRight <= 40) {
    Serial.print("L");

    motorR.write(50); //turn left slightly if wall detected on right
    motorL.write(90);
    delay(20);

    motorR.write(52); //forwards again
    motorL.write(180);

  }

  if (wall < 12 && distFront > 150 && distLeft <= 40) {
    Serial.print("R");

    motorR.write(90); //turn right slightly if wall detected on left
    motorL.write(130);
    delay(25);

    motorR.write(52); //forwards again
    motorL.write(180);

  }

  // the next statement uses `=` insteead of `==`
    if (wall = 12 && distFront <= 150) { // typo & fails
  //if (wall == 12 && distFront <= 150) {

    motorR.write(90); //stop when race is finished
    motorL.write(90);

    wall = 13;

  }
}