Plus or minus X

Using Arduino Programming Questions
1

Is there any way to have the Arduino recognize when it is within, say plus or minus 10 of a number? For example, if a rotary encoder is within X either way of a certain number, it lights an LED?

2

This should light up the pin 13 LED if encoderVal and otherVal happen to be 10 or less away from each other:

void setup() {                
  pinMode(13, OUTPUT);   
  int encoderVal = random(-20, 20);
  int otherVal = random(-20, 20);
  if(abs(encoderVal - otherVal) <= 10) {
    digitalWrite(13, HIGH);
  } else {
    digitalWrite(13, LOW);
  }
}

void loop() {}

Untested.

3

Also untested but shorter:

    digitalWrite(13, abs(encoderVal - otherVal) <= 10);
4

Brilliant, thanks everyone!