confused about sprintf

Using Arduino Programming Questions
1

I have a sample code for a DS1338 RTC that I got from www.hobbytronics.co.uk. In a function to read the RTC there is the following line

char datetime[17]
........


//print the date EG  DD/MM/YY HH:MM:SS 
  sprintf(datetime,"%2.2d/%2.2d/%2.2d %2.2d:%2.2d:%2.2d", monthDay, month, year, hour, minute, second);

and that works fine, but I need to change it from one character array containing the formatted date and time into two character array's, one for date and one for time so I thought it was as simple as this

char date[8];
char time[8];
........

sprintf(date,"%2.2d-%2.2d-%2.2d", month, monthDay, year);
sprintf(time,"%2.2d:%2.2d:%2.2d", hour, minute, second);

but instead of getting date in one variable and time in another I get

05-12-1517:35:56
17:35:56

if I change my code to the following I do get the date all by itself, but of course I am not storing the time in a variable anymore

char date[8];
char time[8];
........

sprintf(date,"%2.2d-%2.2d-%2.2d", month, monthDay, year);
//sprintf(time,"%2.2d:%2.2d:%2.2d", hour, minute, second);

I am sure I am missing something simple, any thoughts?

2

Every string has to terminated with a null - '\0'. That's probably why the first example has 17 elements - 16 characters and one null. So you need to declare time and date as 9 bytes.

3

The first code is wrong as well, array size should be 18.

4

guix:
The first code is wrong as well, array size should be 18.

Yes, because the space character between date and time adds one.

5

thanks got it solved just increased the array sizes and it got it in order