#include <LiquidCrystal.h>

// Initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

// Pin for the button
const int buttonPin = 7;

// Counter variable
int counter = 0;

// Variable to store the button state
int buttonState = 0;
int lastButtonState = 0;

void setup() {
  // Set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  
  // Print the initial counter value
  lcd.print("Counter: 0");
  
  // Set the button pin as input
  pinMode(buttonPin, INPUT);
  
  // Use internal pull-up resistor
  digitalWrite(buttonPin, HIGH);
}

void loop() {
  // Read the button state
  buttonState = digitalRead(buttonPin);
  
  // Check if the button is pressed
  if (buttonState != lastButtonState) {
    if (buttonState == LOW) {
      // Increase the counter
      counter++;
      
      // Clear the previous value
      lcd.clear();
      
      // Print the updated counter value
      lcd.print("Counter: ");
      lcd.print(counter);
    }
    delay(50); // debounce delay
  }
  
  // Save the current button state for comparison in the next loop
  lastButtonState = buttonState;
}

O Level Exam : Practical Question

🖥 Output: