State change detection then while loop - arduino

Question

I would like to stop DC motors after the counter reaches a value e,g num=3 (HIGH's) as shown in the following image:
White line is 3cm thick, black box 30cm squared!
The two IR sensors, int rightSens=30; and int leftSens=32; are working and give a 1 on sensing a black surface, and 0 on any other, i.e. white and in the absence of anything.
I would like the robot to count as in my loop, 3 LOWs incase counting white or 2 HIGHs incase of counting black,then do something e.g. stop, as shown with the while loop.
Something must be wrong, it seems like not counting because it doesn't stop after passing 3 boxes or 3 white lines. any help very appreciated!
int pwm=2; //initializing pin 2 as pwm
int leftMotorin_1=22;//right
int leftMotorin_2=24;
int pwm2=3;
int rightMotorin_3=26;
int rightMotorin_4=28;
//sensor
int rightSens=30;
int leftSens=32;
int rightSensState;
int leftSensState;
//Variables for counting lines
int previousState=0;
int currentState=0;
void setup ()
{
pinMode(pwm,OUTPUT); // set pwm pin as output
pinMode(leftMotorin_1,OUTPUT); //logic pins are also set as output
pinMode(leftMotorin_2,OUTPUT);
pinMode(pwm2,OUTPUT); // set pwm pin as output
pinMode(rightMotorin_3,OUTPUT); //logic pins are also set as output
pinMode(rightMotorin_4,OUTPUT);
//pinMode(obSens,INPUT);
pinMode(rightSens,INPUT);
pinMode(leftSens,INPUT);
}
void readSensors()
{
rightSensState = digitalRead(rightSens);
leftSensState = digitalRead(leftSens);
}
void moveForward()
{
digitalWrite(leftMotorin_1,HIGH);
digitalWrite(leftMotorin_2,LOW);
analogWrite(pwm,150);
digitalWrite(rightMotorin_3,HIGH);
digitalWrite(rightMotorin_4,LOW);
analogWrite(pwm2,150);
}
void stopWheels()
{
//For brake
digitalWrite(leftMotorin_1,LOW);
digitalWrite(leftMotorin_2,LOW);
digitalWrite(rightMotorin_3,LOW);
digitalWrite(rightMotorin_4,LOW);
}
void loop()
{
int count=0;
int num=3;
moveForward();
readSensors();
(currentState=(leftSensState && rightSensState));
if (currentState != previousState );
{
if (currentState==HIGH)
count++;
previousState=currentState;
}
while (count!=num) {
moveForward();
readSensors();
(currentState=(leftSensState && rightSensState));
if (currentState != previousState );
{
if (currentState==HIGH)
count+=1;
previousState=currentState;
}
if (counter == num)
{
stopWheels();
delay(20);
break;
}
}
}