#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() {
  Serial.begin(115200);
  Serial.println("Hello");
  lcd.begin(16, 2);
  lcd.print("Keypad Program");
  delay(1000);
}
void loop() {
  getKey();
  delay(100);
}
void getKey(void) {
  int row = -1, col = -1;
//first scan the row
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;
}
}
//row found
if (row != -1) {
//second scan the col
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);
}