problem with lcd

Other Hardware Displays
1

no display on lcd
#include <OneWire.h>
#include <LiquidCrystal.h>
const int RS=2; //declaration constante de broche
const int E=3; //declaration constante de broche

const int D4=4; //declaration constante de broche
const int D5=5; //declaration constante de broche
const int D6=6; //declaration constante de broche
const int D7=7;
OneWire ibutton (1); // I button connected on PIN 2.

byte buffer[20]; //array to store the Ibutton ID.
LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
void setup(){
lcd.begin(20,4);
Serial.begin(9600);
lcd.print("bjr");
delay(1000);

if (!ibutton.search (buffer)){//read attached ibutton and asign value to buffer
ibutton.reset_search();
delay(200);
return;
}

for (int x = 0; x<8; x++){
lcd.begin(buffer[x],HEX);
}

}
i need your help

2

lcd 16*2

3

Is the backlight comming on?

Have you tried adjusting the pot?

4

Where is loop() ?

Suggestion: Get a simple LCD display working first before you add any pushbutton switches or anything else.
Also: Use the 'code' button so your sketch is formatted like this example:

#include <LiquidCrystal.h>

//LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);      // put your pin numbers here

void setup()
  {
  lcd.begin(16, 2);                          // put your LCD parameters here
  lcd.print("hello, world!");
  lcd.setCursor(0,1)
  lcd.print("it works!");
  }

void loop()
  {
  }

Don