Processing IDE doesn't read data right from serial

I am trying to make an arduino project with arduino ide and processing ide. I started doing a simple test to see the enviornment where I display the numbers 0,1..9 using arduino ide, but processing ide doesn't read it right for some reason and I can't figure out why, it reads weird numbers from serial like 10, 13, 53 and so on (only these numbers, nothing changes). Here is my processing code:

import processing.serial.*;
Serial port;

void setup() {
  port = new Serial(this,"/dev/ttyUSB0",9600);
}
void draw() {
  if(port.available() > 0) {
  int info = port.read();
  println(info);
  println("===");
  }
}

And here is my arduino code:

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  int deg = 0;
  int data = 1;
  for (deg = 0; deg < 10; deg++) {
    Serial.println(deg);
    delay(15);
    delay(1000);
  }
}

Also, the board and processing are using the same port /dev/ttyUSB0. I am running all of this on Ubuntu 20.04. I tried to look on google but can't seem to find anything. Thanks in advance, any tip is welcome.

Solution

Your are sending ASCII from Arduino and reading binary in your Processing IDE. Here is what your sender is doing:

for (deg = 0; deg < 10; deg++) {
  Serial.println(deg);
  ...
}

Serial.println prints the value, meaning it's formatted for display. That means it's converted to ASCII. The output of this will be each number, in ASCII, followed by a new line (thus the 'ln' in the println function):

48 10 13 49 10 13 50 10 13 ... 57 10 13

For example, Serial.println(0) will yield 48 10 13 which is the ASCII code for 0 followed by the new line sequence 10 13 (CR and LF).

Your receiver is doing this:

int info = port.read();
println(info);

Which will read these values as integers and format those numbers as ASCII outputs with new lines. So you will see on your display:

48 
10
13
...

The best way to solve this is to write binary data from Arduino instead of printing the data. On your Arduino, use Serial.write() instead:

for (deg = 0; deg < 10; deg++) {
  Serial.write(deg);
  ...
}