#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>

LiquidCrystal_I2C lcd(0x27, 20, 4);


void setup() {
    lcd.init();
    lcd.backlight();

    Serial.begin(9600);

    Serial.print("false "); Serial.println(false);
    Serial.print("true  "); Serial.println(true);
    Serial.print("LOW   "); Serial.println(LOW);
    Serial.print("HIGH  "); Serial.println(HIGH);

    if (  0) Serial.println("zero");         // no print
    if ( !0) Serial.println("not zero");     // prints
    if (  1) Serial.println("one");          // prints
    if (  2) Serial.println("two");          // prints
    if (100) Serial.println("hundred");      // prints
    if (-10) Serial.println("-10");          // prints
    
    if ("abc123") Serial.println("abc123");  // prints

    // zero is equivalent to false
    // any no-zero is equivalent to true

    char test[][20] = {"hello", "world", "qwerty"};
 
    for (int i = 0; i<3; i++) {
        lcd.setCursor(0, i);  lcd.print(test[i]);
    }
    
    lcd.setCursor(0, 3);
    lcd.print(test[0]);
    lcd.print(test[1]);
    lcd.print(test[2]);

}

void loop() {

}