Code error and I don't know what to do.

I am trying to make a code for reading the temperature in the room and I keep getting error messages and I am not sure what they mean. Here is the entire error message and my code.

const int sensorPin = A0
(const float baselineTemp = 20.0); 
  void setup(){
  Serial.begin(9600); // open a serial post
  for(int pinNumber = 2; pinNumber<5; pinNumber++){
 pinMode(pinNumber, OUTPUT);
    digitalWrite(pinNumber, LOW);
  }
}
void loop(){
  int sensorVal = analogRead(sensorPin);
  Serial.print("Sensor Value: ");
  Serial.print(sensorVal);
  // convert the ADC reading to votage
  float voltage = (sensorVal/1024.0) * 5.0;
  Serial.print(",Volts: ");
  Serial.print(voltage);
  Serial.print(", degrees C: ");
  // convert the voltage to temperature in degrees
  float temperature = (voltage - .5) * 100;
  Serial.println(temperature);
  if(temperature < baselineTemp+2){
    digitalWrite(2, LOW);
     digitalWrite(3, LOW);
     digitalWrite(4, LOW);
  }else if(temperature >= baselineTemp+2 && temperature < baselineTemp+4){
     digitalWrite(2, HIGH);
     digitalWrite(3, LOW);
     digitalWrite(4, LOW);
}else if(temperature >= baselineTemp+4 && temperature < baselineTemp+6){
     digitalWrite(2, HIGH);
     digitalWrite(3, HIGH);
     digitalWrite(4, LOW);
  }else if(temperature >= baselineTemp+6){
     digitalWrite(2, HIGH);
     digitalWrite(3, HIGH);
     digitalWrite(4, HIGH);
  }
  delay(1);
}
    



[Error]

2:2: error: expected primary-expression before 'const'
2:33: error: 'A0' cannot be used as a function
 In function 'void loop()':
22:20: error: 'baselineTemp' was not declared in this scope



Hopefully someone can help!
const int sensorPin = A0

Did forget to end the statement correctly ?

(const float baselineTemp = 20.0);

What are the brackets for ?

Hi KitKat47,

a programming IDE is a bit more complex than a TV-remote-control.
This means you have to learn more than one minute which would be enough for a TV-remote-control.
Press the red button to switch on etc…

If you don’t want to get stumped every three minutes and wait at least 15 minutes until an answer is given in the forum
you have to learn how the Arduino-IDE works. And you have to learn how the programming language works.

The error-messages do have numbers
The number is the line of code inside the code-texteditor.
If you haven’t switched on the linenumbers in the texteditor you should do it right now

click file preferences show line numbers

so in your error-message
2:2: error: expected primary-expression before ‘const’

the “2” points you to line number 2. In line number 2 something is wrong

We (the other forum-members can see that you are a beginner. This post above is your second post.
So the forum-members have some forbearance. But you would eat up all forbearance quickly if you would post a lot more questions like this. Your questions should show that you walk ab the learning-curve. Your questions should show that you put some effort into rise your own knowledge-level

best regards Stefan