#include <LiquidCrystal.h>
LiquidCrystal lcd(18, 5, 17, 16, 4, 0);
const int keyPadRow[4] = {12, 14, 27, 26};
const int keyPadCol[4] = {25, 33, 32, 13};
char numbers[4][4] = {
  '1', '2', '3', 'A',
  '4', '5', '6', 'B',
  '7', '8', '9', 'C',
  '*', '0', '#', 'D',
};
void setup() {
  // set up the LCD's number of columns and rows:
  Serial.begin(115200);
  lcd.begin(16, 2);
  lcd.print("Keypad Program");
  delay(100);
}
void loop() {
  getKey();
  delay(300);
}
void getKey(void) {

  int row = -1, col = -1;
  for (int i = 0; i < 4; i++) {
    pinMode(keyPadRow[i], INPUT_PULLUP);
    pinMode(keyPadCol[i], OUTPUT);
    digitalWrite(keyPadCol[i], LOW);
  }
  for (int i = 0; i < 4; i++) {
    if (digitalRead(keyPadRow[i]) == 0) {
      row = i;

    }

  }
  if (row != -1) {
    for (int i = 0; i < 4; i++) {
      pinMode(keyPadCol[i], INPUT_PULLUP);
      pinMode(keyPadRow[i], OUTPUT);
      digitalWrite(keyPadRow[i], LOW);
    }
    for (int i = 0; i < 4; i++) {
      if (digitalRead(keyPadCol[i]) == 0) {
        col = i;
        lcd_display_num(numbers[row][col]);

      }
    }
  }
}
void lcd_display_num(char num) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Key Pressed: ");
  lcd.print(num);
  delay(500);

}