#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define  SCREEN_WIDTH 128
#define  SCREEN_HEIGHT 64
int redled = 11;
int trigpin = 2;
int echopin = 3;
float distance;
int duration;

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)){
  Serial.println("SSD1306 allocation failed");
  for(;;);
}
pinMode(redled, OUTPUT);
pinMode(trigpin, OUTPUT);
pinMode(echopin, INPUT);
display.setTextColor(SSD1306_WHITE);
display.setTextSize(1);
}

void loop() {
digitalWrite(trigpin, LOW);
delay(500);
digitalWrite(trigpin, HIGH);
delay(500);
digitalWrite(trigpin, LOW);
duration = pulseIn(echopin, HIGH);
distance = duration * 0.034 / 2;
delay(500);
// clear display
display.clearDisplay();
//set text sizee
display.setTextSize(2);
// set cursor
display.setCursor(0, 0);
//print text
display.println(distance);
display.display();
delay(500);
}