Size of array

Projects Programming
1

hello i need to know the size of an array im filling, i have try the function sizeof which returns me the value which i gave at the begining, for example:

char password[4];
up = 0;
sizee = 0;

char key = keypad.getKey();

if ( key != NO_KEY )
{
password[up] = key;
sizee = sizeof(password);
lcd.setCursor(0,1);
lcd.print(sizee);
up++;
}

im using a keyboard, when i press a button this should me save the key in password array then sizeof returns me the begining size i gave which is 4, but i want it returns me the real size it is filled, so when i press 2 keys it should returns 2, etc

2

sizeof returns the size of the allocated memory for the array. This will never change.

To find out how long a string is (string as in null-terminated character array) use the strlen() function.

3

Doesn't the variable "up" keep track of what you want?

(Please use code tags when posting code)

4

"up + 1" will give you what you are looking for without any other functions needed.

5

I just need a function who returns me the number of positions ocuppied inside the array

6

There isn't one.

There is no such thing as an unoccupied position in an array - every entry has a value.

You could go through and count the number of entries that match a certain criteria.

7

As has been mentioned numerous times the "up" variable tells you how many valid key values are in the array (which is I assume what you mean)

if ( key != NO_KEY )   
  {
    password[up] = key;
    lcd.setCursor(0,1);
    up++;
    lcd.print(up);
}

This should print the number of keys entered.

Rob