#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(){
  lcd.begin(16,2);
  lcd.print("KeyPad program");
  delay(1000);
}
void loop(){
 getKey();
 delay(100);
  }
  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(1000);

  }