const int intPin=2;
volatile int counter=0;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(intPin, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(intPin), counterFCH, HIGH);

}

void loop() {
  // put your main code here, to run repeatedly:
  Serial.print("Switch pressed:");
  Serial.print(counter);
  Serial.print('\n');

}

void counterFCH() {
  counter++;
  delay(100);
}