Arduino Power Supply 0 - 5V

//Arduino Power Supply 0-5Volt
#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 10, 5, 4, 3, 2);
int potPin = A0;
int readValue;
float Voltage;

void setup(){
pinMode(potPin, INPUT);
lcd.begin(16, 2);
}

void loop(){
readValue = analogRead(potPin);
Voltage = (5./1023)*readValue;
lcd.setCursor(0,0);
lcd.print("Voltage = ");
lcd.setCursor(0,1);
lcd.print(Voltage, 3);
lcd.print("V");
delay(250);
}