Question

How to fetch first two bytes from the string “DDMMYYHHMMSS” and fill the below structure.

mytime.tm_sec  = SS;   // Seconds      (0-59)
mytime.tm_min  = MM;   // Minutes      (0-59)
mytime.tm_hour = HH;   // Hours        (0-23)
mytime.tm_mday = YY;   // Day of Month (1-31)
mytime.tm_mon  = MM;   // Month        (0-11)
mytime.tm_year = DD;   // Year         (no. of years since 1900)

Answer 1

I’m assuming this is homework, so I won’t give you the full answer.

Let’s split this problem into bits.

1) Given a string, do you know how to extract a sub-string? E.g., can you figure out how to accomplish this:

char sample[] = "DDMMYYHHMMSS";
char *dd;
// code you need to figure out
printf("%s", dd); // should print “DD”

Hint: Look up strncpy().

2) Once you’ve figured that out, do you know how to convert a string of digits to a number? E.g., can you accomplish this:

char dd[] = "32";
int mday;
// code you need to figure out
printf("%d", mday); // should print “32”

Hint: Look up sscanf() & atoi().

At this point, combining those two techniques should be straightforward. By all means ask more if you need more help.