Stored values in char array not reading back what is being stored?

Projects Programming
1

Basically I'm writing some code for a TFT screen. In the program I have made buttons (a numberpad) and as the buttons for the numbers are pressed they are stored in an array. I plan on having the numbers update and display on the screen as they are pressed but am for now sending them to the serial monitor for debugging. I am aware that serial monitor prints chars in ASCii, but the chars im getting are not the ascii of what I am storing as the buttons are pressed.

The picture attached below shows what is happening in the serial monitor... I press a 1 and get an O, press a 2 and get a Q, etc. I tried printing to the TFT screen as well, the same strange characters are printed instead of the numbers stored so its not a serial thing and more a my usage or misunderstanding of how to use char arrays. What am I missing here that numbers are being stored weird and returned as strange chars?

Thanks in advance

Relevant code:

char POarray[11] = "***********";
int k = 0;
void PO()
{
  while(k<=10)
  {
  retrieveTouch();
          
    if (Z > MINPRESSURE && Z < MAXPRESSURE)
    {

      //Check if element clicked is in left column
      if (Y > (leftColPositionX - BOXSIZE) && Y < (leftColPositionX - 5))
      {
        
        //Serial.println("LEFT");
        //Check if element clicked is in row 1
        if (X > topbot && X < toptop)
        {
          Serial.println("1");
          POarray[k] = "1";
          Serial.println(POarray);
          k++;
          delay(400);
          tft.setCursor(100, 10);
          tft.setTextColor(RED);
          tft.setTextSize(3);
          tft.print(POarray);
        }
        //Check if element clicked is in row 2
        else if (X > mid && X < topbot)
        {
          Serial.println("4");
          POarray[k] = "4";
          Serial.println(POarray);
          k++;
          delay(400);
        }
        //Check if element clicked is in row 3
        else if (X < mid && X > bottop)
        {
          Serial.println("7");
          POarray[k] = "7";
          Serial.println(POarray);
          k++;
          delay(400);
        }
        //Check if element clicked is in row 4
        else if (X < bottop && X > botbot)
        {
          Serial.println("0");
          POarray[k] = "0";
          Serial.println(POarray);
          k++;
          delay(400);
        }
      }
      //Check if element clicked is in mid column
      else if (Y > (midColPositionX - 6 - BOXSIZE) && Y < (midColPositionX - 10))
      {
        //Check if element clicked is in row 1
        if (X > topbot && X < toptop)
        {
          Serial.println("2");
          POarray[k] = "2";
          Serial.println(POarray);
          k++;
          delay(400);
        }
        //Check if element clicked is in row 2
        else if (X > mid && X < topbot)
        {
          Serial.println("5");
          POarray[k] = "5";
          Serial.println(POarray);
          k++;
          delay(400);
        }
        //Check if element clicked is in row 3
        else if (X < mid && X > bottop)
        {
          Serial.println("8");
          POarray[k] = "8";
          Serial.println(POarray);
          k++;
          delay(400);
        }
        //Check if element clicked is in row 4
        else if (X < bottop && X > botbot)
        {
          Serial.println("0");
          POarray[k] = "0";
          Serial.println(POarray);
          k++;
          delay(400);
        }
      }
      else if (Y > (rightColPositionX - 14 - BOXSIZE) && Y < (rightColPositionX - 20))
      {
        //Check if element clicked is in row 1
        if (X > topbot && X < toptop)
        {
          Serial.println("3");
          POarray[k] = "3";
          Serial.println(POarray);
          k++;
          delay(400);
        }
        //Check if element clicked is in row 2
        else if (X > mid && X < topbot)
        {
          Serial.println("6");
          POarray[k] = "6";
          Serial.println(POarray);
          k++;
          delay(400);
        }
        //Check if element clicked is in row 3
        else if (X < mid && X > bottop)
        {
          Serial.println("9");
          POarray[k] = "9";
          Serial.println(POarray);
          k++;
          delay(400);
        }
        //Check if element clicked is in row 4
        else if (X < bottop && X > botbot)
        {
          Serial.println(".");
        }
      }
    }
    
  }
}

serialsnip.PNG

2

Everywhere you insert a character into the array, change from this:

POarray[k] = "1";

to

POarray[k] = '1';

Use single-quotes for character (versus null-terminated string) operations like this. Once you have that sorted, try it again. (I didn't look any further than the first instance of this.)

FWIW, there are ways to streamline that code so you don't have an endless chain of if/else statements.

3

Thank you. Problem solved... Instead of using if else statements what methods should I look into? would these other methods save program size?