Error de compilación ISO C++ forbids comparison between pointer

HELP
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AND DID THE CODE ERROR ARDUINO BRAND ME BUT when compiling. THIS IS THE CODE

void setup()
{
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);
pinMode(12, OUTPUT);
pinMode(13, OUTPUT);

Serial.begin(9600);
}

void loop()
{
char dato = Serial.read();
if (dato =="a")digitalWrite(2,HIGH);
if (dato =="b")digitalWrite(2,LOW);
if (dato =="c")digitalWrite(3,HIGH);
if (dato =="d")digitalWrite(3,LOW);
if (dato =="e")digitalWrite(4,HIGH);
if (dato =="f")digitalWrite(4,LOW);
if (dato =="g")digitalWrite(5,HIGH]);
if (dato =="h")digitalWrite(5,LOW);
if (dato =="i")digitalWrite(12,HIGH);
if (dato =="j")digitalWrite(12,LOW);
if (dato =="k")digitalWrite(13,HIGH);
if (dato =="l")digitalWrite(13,LOW);
}

   if (dato =='a')
digitalWrite(5,HIGH]);

There’s your next problem.

Please don’t SHOUT

Use 'a' instead of "a".

You only want to compare a single character, not a whole string (and you were actually comparing the pointer to the string).