Help with displaying array on 16*2 LCD


im trying to display an array on lcd after getting it from the user as input

i want to get 4 digits as input, put them on the array ( temp ) after that display the hole array on the lcd

here is the code for the array input (on void loop)

  char temp[] = {} ;
     key = customKeypad.waitForKey();
     if(key != NO_KEY)

i had no problems with the input code and it was working as it should, but after i wrote the code of displaying the program stopped getting key as input at 1=2 , ended the while and printed a symbol i don’t know

i wrote this for displaying


so can someone help me with this problem please ??

i wrote the code of displaying the program stopped getting key as input at 1=2 , ended the while and printed a symbol i don’t know

I do not know what that means. Can you post the code that you are talking about and a picture of the output on the LCD?


That code will print one element of the temp array.

Is the total code a secret? It's more or less impossible to give any advice on those pices of code.

char temp[] = {} ;A zero element array?

This shows how to print an array to an LCD using a for loop.

#include <hd44780.h>
#include <hd44780ioClass/hd44780_pinIO.h> // Arduino pin i/o class header

const byte rs = 12, en = 11, db4 = 4, db5 = 5, db6 = 6, db7 = 7;

hd44780_pinIO lcd(rs, en, db4, db5, db6, db7);

byte temp[] = {1, 2, 3, 4};

// LCD geometry
const int LCD_COLS = 16;
const int LCD_ROWS = 2;

void setup()
   lcd.begin(LCD_COLS, LCD_ROWS);
   lcd.print("Hello, World!");
   lcd.setCursor(0, 1); //second row
   // use a for loop to print the contents of an array
   for (byte n = 0; n < sizeof(temp) / sizeof(temp[0]); n++)
      lcd.print("  ");

void loop()
{   }  // everything happens in setup()

sorry for not posting the total code sir but its about 800 lines i cant post it here so i have just posted the lines related to the topic i want

My answer is too long to write here.

From the forum guidelines:

Post a complete sketch (program code)! If you don’t you waste time while people ask you to do that. However, with coding problems, if possible post a “minimal” sketch that demonstrates the problem - not hundreds of lines of code. If the problem goes away in the minimal sketch, it wasn’t where you thought it was.

If you will not write a minimal sketch you can attach the code if it is over the 9000 character limit. See #8 in the linked guidelines.

thank you all, i have solved it

i have changed the array to be

char temp [] = {0,0,0,0};

and made a for loop for the displaying line to be

for ( i = 0 ; i<4 ; i++ )

now its working correctly, and sorry for not posting the total code again i know it may be rude for some of you but my problem wasnt worth it to post the total code

sorry for you all and thank you again :slight_smile: :slight_smile: :slight_smile: