Clear the array and re-store the new value in array

Using Arduino Programming Questions
1

Here is the code which I did. I want a function that can return to the beginning of the void loop().
Now If I press the '#', the array had been set to empty which is what I expected. But it did not save the value to the array after I press the key again. As I know, the loop() will execute the function in order. So, I do not know why it is not let me put value into the array again after I empty it.

#include<Keypad.h>
const byte ROWS = 4;
const byte COLS = 4;
unsigned int time;

// Array to represent keys on keypad
char Keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

// Connections to Arduino
byte rowPins[ROWS] = {6, 7, 8, 9};
byte colPins[COLS] = {10, 11, 12, 13};
 
// Create keypad object
Keypad customKeypad = Keypad(makeKeymap(Keys), rowPins, colPins, ROWS, COLS);
int theArray[4] = { 0 };
byte arrayIndex = 0;
int guess = 0;

void setup()
{
  Serial.begin(9600);
	// Declare pins as Outputs
	pinMode(stepPin, OUTPUT);
	pinMode(dirPin, OUTPUT);
}
void loop() {
  char customKey = customKeypad.getKey();

  if (customKey) 
  {
    Serial.println(customKey);  // print the key i pressed
  }

  if (customKey == '1' || customKey == '2'|| customKey == '3'|| customKey == '4'|| customKey == '5'|| customKey == '6'|| customKey == '7'|| customKey == '8'|| customKey == '9'|| customKey == '0') 
  {
    if (arrayIndex < 5) // If the array length smaller than 5, save the pressed value in array
    {
      theArray[arrayIndex] = customKey - '0';
      arrayIndex++;
    }
  }

   if (customKey == '*') // after the array is reach enough length, press '*' to print the array out
  {
    int guess = (1000 * theArray[0]) + (100 * theArray[1] + (10 * theArray[2]) + theArray[3]);
    Serial.println(guess);
  }

   if (customKey == '#') // press '#' to set the array empty
  {
    memset(theArray, 0, sizeof(theArray));
    arrayIndex == 0;  
    return 0;
  }
  // here I want a function that can return to the beginning of the void loop()
  // The problem is after I press the '#', the array had been set to empty "0"
  // But It did not save the value to the array after I press the kay again
}
2

Your topic was MOVED to its current forum category which is more appropriate than the original as it has nothing to do with Installation and Troubleshooting of the IDE

3

Why not--?

arrayIndex = 0;
//return 0;
1 Like
4

since @GolamMostafa has found your error, instead of the above, consider (see ASCII)


   if ('0' <= customKey || customKey <= '9')

and instead of

consider doing following with each numeric key press

guess= 10*val + customkey-'0';

where guess is a global and is process/reset when '*' or '#' are pressed

5

For a full explanation see Keypad data entry. A beginners guide

6

Why is your array is of type int?

A keypress ( 0 to 9) in the Keypad returns ASCII code which being subtracted by '0' gives a byte value. For example: pressing Key-9 gives 0x09 (0x39 - '0' = 0x39 - 0x30 = 0x09).

7

I think you want: if ('0' <= customKey && customKey <= '9')

8

yes, thanks

9

Is not the following a Logical Style?
if(customKey >= '0' && customKey <= '9')

10

It is much more logical (and readable) in my opinion, but there are those here who prefer to put the constant value first in comparisons so that where = is used by mistake instead of == the compiler reports an error

1 Like
11

wouldn't the following (if possible) be easier to understand
'0' <= customKey <= '9'

12

Yes, if I can read like this:

char customeKey;
if('0' <= customKey <= '9')
{
     Serial.println(customeKey);
}
13

Not for me

if (customKey >= '0' and <= '9')

would be better (for me)

If we are going to invent new syntax then why not

if (customKey between '0 and '9')
14

because i thing 0 <= x <= 9 is more mathematical

15

I prefer my code to be readable, almost in English if possible. The compiler can then work whatever magic it wants without bothering me

16

so you're suggesting 0 <= x <= 9 is less readable?

doesn't it depend on what your coding? i spent a lot of time writing code on signal processors.

17

Yes

Read it to me in English

18

if x is greater that 0 and less than 9

19

That is not reading it, rather it is interpreting it.

That is not the same thing at all

20

does "between" imply Inclusiveness?