keypad errors

Using Arduino Programming Questions
#1

Ok, Another problem. I am building a keypad door lock, and all the other parts work. I have LEDs to print when the codeis right or wrong. But for some reason, it keeps returning the red LED, even when the code is correct! Please help me. code:

#include <Keypad.h>
char pass[3] = "";
const int led1=12;
const int led2=10;
const int led3=11;
const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
//define the cymbols on the buttons of the keypads
char hexaKeys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {9, 8, 7, 6}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {5, 4, 3, 2}; //connect to the column pinouts of the keypad

//initialize an instance of class NewKeypad
Keypad customKeypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS); 
void strcat(char* original, char appended)
{
   while (*original++)
       ;
   *original++ = appended;
   if (appended)
       *original = '\0';
}
void setup(){
  Serial.begin(9600);
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  
   digitalWrite(led1, HIGH);
   digitalWrite(led2, HIGH);
   digitalWrite(led3, HIGH);
   delay(2000);
   digitalWrite(led1, LOW);
   digitalWrite(led2, LOW);
   digitalWrite(led3, LOW);
}
  
void loop(){
  char customKey = customKeypad.getKey();
  if (customKey){
    strcat(pass, customKey);
    Serial.println(customKey); 
    if(customKey=='#'){
      if(pass[3]==['2', '1', '2']){
        Serial.println(pass);
        char pass[3]="";
        digitalWrite(led3, HIGH);
        delay(10000);
        digitalWrite(led3, LOW);
        
      }
      else{
        Serial.println(pass);
        char pass[3]="";
        digitalWrite(led1, HIGH);
        delay(2000);
        digitalWrite(led1, LOW);
      }
    }

  } 
  }

I am a noob, so i need lots of help.
thanks.

#2 
if(pass[3]==['2', '1', '2']){

You can't compare a whole array at once like that. You can use memcmp. This is asking if the (non-existant) fourth element of pass is equal to something that a single char could never equal.

There are tons and tons of tutorials and examples of keypad locks out on the internet. I suspect you would do some good to study through a few of them.

#3