arduino program 3d printer

Projects Programming
4

Here is the code formatted better and in code tags

#include <Adafruit_GFX.h>
#include <Adafruit_SPITFT.h>
#include <Adafruit_SPITFT_Macros.h>
#include <gfxfont.h>
#include <Adafruit_SSD1306.h>
#include <SPI.h>
#include <Wire.h>
#define OLED_RESET 4
Adafruit_SSD1306 display(OLED_RESET);

int counter = 0;
int infofil = 0;
int infobuse = 0;
int infolit = 0;

void setup()
{
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
}

void loop()
{
  display.setTextSize(1);
  display.setTextColor(WHITE);
  while (1)
  {
    if (infofil = 0);
    display.setCursor(0, 0);
    display.println("DETECTION DU FIL=OUI");
    display.display();
    if (infofil != 0)
      display.setCursor(0, 0);
    display.println("DETECTION DU FIL=NON");
    display.display();
    infolit = Serial.read();
    display.setCursor(0, 1);
    display.println("TEMPERATURE LIT CHAUFFANT=", infolit);
    display.display();
    infobuse = Serial.read();
    display.setCursor(0, 2);
    display.println("TEMPERATURE BUSE=" infobuse);
    display.display();
  }
}

Let's start with the easy stuff

   if (infofil = 0);

This line of code sets infofil to 0 rather than testing whether it is zero.
Even if you used == instead of = to turn it into a test then the only code depending on its value being zero is the semicolon. I am sure that is not what you meant to happen.

Which lines of code should be executed if infofil is equal to zero ?

How much do you know about programming in C ?
Have you looked at and tried the examples in the IDE ?