Code gives me error (else without a previos if) when uploading the code

Projects Programming
1

Hello. I'm new to programming and for some time i have problem with "if" and "else" function. Sometimes when i write my code to practice and when i upload it it gives me error that there is no "if" before "else". I check my code a couple of times but i dont find any easy to find errors(missed bracets or semi colum). At the moment I'm trying to display information on an oled display from IR sensor ( if it detects something or not).

Here is the code:

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 
#define SCREEN_HEIGHT 64
#define OLED_RESET  -1 
#define SCREEN_ADDRESS 0x3C 
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

 

const int sensor = 18;

void setup() {
   if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS, OLED_RESET)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;); 
  }
  // put your setup code here, to run once:
  Serial.begin(115200);
 
}

void loop()
{
   int data = digitalRead(sensor);
  if (data == LOW);
  {
    display.clearDisplay();
    display.setTextColor(WHITE);
    display.setTextSize(2);
    display.setCursor(0,0);
    display.println("Detected");
    display.display();
    
  }
  else
  {
     display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(2);
  display.setCursor(0, 0);
  display.println("Not Detected");
  display.display();
  }
 
}

I try to use yt/github or my previous codes as reference for my current one.
Any tips for the code will be of big help.

2

Any tips for the code will be of big help.

Hello mrt190

Welcome to the worldbest Arduino forum ever :smiley:

Change

if (data == LOW);

to

if (data == LOW)

and try again.

2 Likes
3

The ';' is the culprit here. Remove the ;
Further, since the only difference is the println statement you might want to change it to:


void loop()
{
   int data = digitalRead(sensor);
   display.clearDisplay();
   display.setTextColor(WHITE);
   display.setTextSize(2);
   display.setCursor(0,0);
   if (data == LOW)  display.println("Detected");
  else display.println("Not Detected");
   display.display();

I omitted the curly brackets {}. When only one stament is used after if, you do not need them.

1 Like
4 
void loop()
{
   bool data = digitalRead(sensor);
   display.clearDisplay();
   display.setTextColor(WHITE);
   display.setTextSize(2);
   if (data)display.println("Not ");
   display.println("Detected");
   display.display();
3 Likes
5

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.