Elegoo Smart Robot line following code

//www.elegoo.com
//2016.09.12

int in1=9;
int in2=8;
int in3=7;
int in4=6;
int ENA=10;
int ENB=5;
 int ABS=130;
 void _mForward()
{
  analogWrite(ENA,ABS);
  analogWrite(ENB,ABS);
  digitalWrite(in1,LOW);
  digitalWrite(in2,HIGH);
  digitalWrite(in3,LOW);
  digitalWrite(in4,HIGH);
  Serial.println("go forward!");
}

void _mBack()
{
  analogWrite(ENA,ABS);
  analogWrite(ENB,ABS);
  digitalWrite(in1,HIGH);
  digitalWrite(in2,LOW);
  digitalWrite(in3,HIGH);
  digitalWrite(in4,LOW);
  Serial.println("go back!");
}

void _mleft()
{
   analogWrite(ENA,ABS);
   analogWrite(ENB,ABS);
   digitalWrite(in1,LOW);
   digitalWrite(in2,HIGH);
   digitalWrite(in3,HIGH);
   digitalWrite(in4,LOW);
   Serial.println("go left!");
}

void _mright()
{
   analogWrite(ENA,ABS);
   analogWrite(ENB,ABS);
   digitalWrite(in1,HIGH);
   digitalWrite(in2,LOW);
   digitalWrite(in3,LOW);
   digitalWrite(in4,HIGH);
   Serial.println("go right!");
} 
void _mStop()
{
   digitalWrite(ENA,LOW);
   digitalWrite(ENB,LOW);
   Serial.println("Stop!");
} 

void setup() 
{
  Serial.begin(9600);
}

void loop() {
  int num1,num2,num3;
  num1=digitalRead(11);    
  num2=digitalRead(4);
  num3=digitalRead(2); 
   if((num1==0)&&num2&&num3) 
   {
    _mleft();          //The sensor detected that right car turn left immediately when it meets black line 
    delay(2);
    while(1){
    num2=digitalRead(2);         //Cycle to judge degree of intermediate sensor,
    if(num2==1)
    {  _mleft();                     //If num2==1 does not go to the middle position, continue to turn left.
     delay(2);}
     else
     break;                      //Detection of num2==0 instructions turned over, out of the loop, detection of three sensors’ statusand then make appropriate action
   }                                       //The following and so on
   }    

  else if(num2&&num1&&(num3==0))
   {
    _mright();
    delay(2);
    while(1)
    {
     num2=digitalRead(2);
    if(num2==1){
      _mright();  
     delay(2);}
     else
      break;
    }
   }
  else
  {
    _mForward(); 
    delay(2);
  } 
}

So I have this line following code and I uploaded it to my Elegoo smart robot for a project I am doing. When I went to test the code for some reason the car won't seem to trun left olny right. Is there something in the code that I need to change to make it turn left? Also it would be helpful to me if who ever answers this to show me where in the code the that needs to be changed. Also can anyone tell me what ENB and ENA stand for in the code as well as ABS.

At a guess

ENA ENable A
ENB ENable B
ABS A (and) B Speed

  num1 = digitalRead(11);
  num2 = digitalRead(4);
  num3 = digitalRead(2);
.....
      num2 = digitalRead(2);       //Cycle to judge degree of intermediate sensor,

It looks like you start to read your right sensor instead of center sensor when you need to go back on track. Same in both right and left detection.

int in1=9;
int in2=8;
int in3=7;
int in4=6;

Are this INPUTs to the Arduino? If not, why are you using in in the name?

Code is a copy from elegoo tutorial. Naming comes from basic L298N board.

Naming comes from basic L298N board.

But, that is not the board being programmed. The pins on that board are INPUT. The pins that they are connected to on the Arduino need to be OUTPUT pins, and the names should reflect the purpose, not what the labels are on the board that they are connected to.

I'll get off my soapbox now.