I have read in a time in the format HH:MM:SS from a file into a string variable.
The problem i have is i need to subtract the times from each other to find the difference.
Is there such a thing as a time variable which allows subtraction, or is there another way to do this?
Thanks guys.
You can use the time() & localtime() functions
Code:struct tm * curtime; time_t bintime; time(&bintime); curtime = localtime(&bintime);
Thanks for the reply, unfortunately i'm unsure how to use this to solve my problem.
Say i have 2 times:
12:34:50
12:34:46
how could i use the time function to subtract these and get an answer of 4. Remembering that i am storing the time in a character array.
Code:char tm1 = "12:34:50", tm2 = "12:34:46"; int iDiff(0); tm1[2]=tm1[5]=tm2[2]=tm2[5]=0; iDiff = (atoi(tm1)-atoi(tm2))*3600 + (atoi(tm1+3)-atoi(tm2+3))*60 + (atoi(tm1+6)-atoi(tm2+6)); // Calculate difference in seconds
I just wrote it down quickly, i didn't have the time to test it..
It's ment to be a pointer to how it can be done
thanks for your help, it doesn't give the correct answer but i get the jist.
am i right in thinking that
tm1[2]=tm1[5]=tm2[2]=tm2[5]=0;
shoulde be
tm1[2]=tm1[5]=tm2[2]=tm2[5]= '0';
now to work on the equation.
Thanks again
No, setting them to 0 terminates the string at that position. Setting it to '0', only pads the string with '0'
printf(tm); // Displays hours
printf(tm+3); // Displays minutes
printf(tm+6); // Displays seconds
Last edited by knutso; 05-21-2003 at 04:53 AM.
ok sorry, i get it now. It works great.
>Salem - how did you mean the algorithm is broken, it works fine for me.
I have:
Thanks for your helpCode:char tm1[9] = "12:34:50"; char tm2[9] = "12:35:46"; int iDiff = 0 ; tm1[2]=tm1[5]=tm2[2]=tm2[5]=0; iDiff = (atoi(tm1)-atoi(tm2))*3600 + (atoi(tm1+3)-atoi(tm2+3))*60 + (atoi(tm1+6)-atoi(tm2+6)); cout << iDiff ;
Knutso, your algorithm won't work if its a single-digit hour.
Try this:
Code:#include <iostream> #include <cstdio> int main( void ) { char tm1[] = "12:34:50"; char tm2[] = "12:34:46"; int h1, m1, s1; int h2, m2, s2; sscanf( tm1, "%d:%d:%d", &h1, &m1, &s1 ); sscanf( tm2, "%d:%d:%d", &h2, &m2, &s2 ); std::cout<<"Time difference is: "<<( h1 - h2 ) * 3600 + ( m1 - m2 ) * 60 + ( s1 - s2 )<<std::endl; }
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Or you could use something like this to store the times, then use difftime()
Code:struct tm mytmdate; time_t tim; mytmdate.tm_year = 2003 - 1900; mytmdate.tm_mon = 4; mytmdate.tm_mday = 1; mytmdate.tm_hour = 20; mytmdate.tm_min = 10; mytmdate.tm_sec = 0; mytmdate.tm_isdst = -1; tim = mktime(&mytmdate); printf("Time is %s\n", ctime (&tim));
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