How to convert integer to string?

[antonius]

Posted on January 02, 2014 at 11:47

struct tm time;

   char year[50]; Guys, I want to display year into LCD screen but I got 00 on LCD, any clues on how to do it ? thanks  printf(''Time: %d-%d-%d   %02d:%02d:%02d \r\n'', time.tm_year, \                    time.tm_mon+1, time.tm_mday,\                    time.tm_hour, time.tm_min, time.tm_sec);     sprintf(year,''%.2f'',time.tm_year);     lcd_string(year); #!complicated

[chen]

Posted on January 02, 2014 at 12:10

Hi

The 'printf' can depend on the library that you are using, which can depend on the tool chain that  you are using. IAR tool chain does not support the '%f' in the 'basic' library - you have to use the 'full' library but that then adds 20K of binary (IAR provide the implementations of the STD libraries - you choose which one to use basic, full + another which I forget now). So what tool chain are you using?

[antonius]

Posted on January 02, 2014 at 12:15

I'm using MDK-ARM, isn't it gcc ?

[antonius]

Posted on January 02, 2014 at 12:21

I got this warning :

..\USER\RTC\RTC_Time.c(481): warning:  #167-D: argument of type ''char *'' is incompatible with parameter of type ''unsigned char *'' code :  struct tm time;    char year[50];    time = Time_GetCalendarTime();    printf(''Time: %d-%d-%d   %02d:%02d:%02d \r\n'', time.tm_year, \                    time.tm_mon+1, time.tm_mday,\                    time.tm_hour, time.tm_min, time.tm_sec);     sprintf(year,''%02d'',time.tm_year);     lcd_string(year);

[antonius]

Posted on January 02, 2014 at 12:23 it's running but freezed in the middle.....any ideas ?

[chen]

Posted on January 02, 2014 at 12:30

Hi

Where is the printf going to ? ''sprintf(year,''%.2f'',time.tm_year);'' will probably not be null terminated - so when ''lcd_string(year);'' executes - it probably goes on beyond the buffer you allocated and crashed.

[chen]

Posted on January 02, 2014 at 13:14

Hi

''sprintf(year,''%.2f'',time.tm_year);'' will probably not be null terminated'' Forget that - apparently it does Null terminate.

[trevor23]

Posted on January 02, 2014 at 13:45

At least 2 problems here:

1. Should be ''%02d'' not ''%.2f''2. tm_year is an integer containing number of years since 1900. Therefore to get year as 2 digits would be something like this ''sprintf(year, ''%02d'', (time.tm_year + 1900) % 100);''

[Tesla DeLorean]

Posted on January 02, 2014 at 14:20

2. tm_year is an integer containing number of years since 1900. Therefore to get year as 2 digits would be something like this ''sprintf(year, ''%02d'', (time.tm_year + 1900) % 100);''

Same two digits without the addition, mind.

[trevor23]

Posted on January 02, 2014 at 16:21

Same two digits without the addition, mind.

Indeed Clive