• State Not Answered
  • Locked Locked
  • Replies 7 replies
  • Subscribers 21 subscribers
  • Views 1192 views
  • Users 0 members are here
2025 survey

We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.

Options
Related
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

cast?

Leonhard Fuchs

Does anybody know, how one have to cast an operation correctly? And is it necessary to tell the compiler that a constant is unsined long

#define dword unsigned long
unsigned char ucH;    //hours
unsigned char ucM;    //minutes
unsigned char ucS;    //seconds
dword ulTime;         //Time in s

GetTime(...);
ulTime = ucS + ucM*60 + ucH*3600;
[..]
this won't work! How do I have to cast the calculation?

ulTime = (dword)(ucS + ucM*60 + ucH*3600);
or
ulTime = ucS + (dword)ucM*60 + (dword)ucH*3600);
or ???

I have tried to find any written description (K&R, C166-Reference) but I could't find anything about this theme!

Do I have to use 3600 or 3600ul?

Thank you
...Leo

Parents
  • 0 in reply to Gary Culp

    ucS and ucM are unsigned char, so they each have a maximum value of 255. 255 + 60 * 255 is 15555, well within the range of an int, so the constant sixty doesn't have to be an unsigned long.

    Ahhh. Yes. You are right about that. I noticed that the multiplication with 3600 would definitely be out of range and assumed that the multiplication with 60 would be as well (assuming that NOINTPROMOTE is used.)

    Jon

Reply
  • 0 in reply to Gary Culp

    ucS and ucM are unsigned char, so they each have a maximum value of 255. 255 + 60 * 255 is 15555, well within the range of an int, so the constant sixty doesn't have to be an unsigned long.

    Ahhh. Yes. You are right about that. I noticed that the multiplication with 3600 would definitely be out of range and assumed that the multiplication with 60 would be as well (assuming that NOINTPROMOTE is used.)

    Jon

Children
No data