Solved

clock() not working

Posted on 2002-03-06
11
504 Views
Last Modified: 2010-05-18
#include <time.h>

....
printf("cpu= %g",clock()/CLOCKS_PER_SEC);
.....

output: cpu= 0
0
Comment
Question by:anothercto
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 6
  • 2
  • 2
  • +1
11 Comments
 
LVL 86

Expert Comment

by:jkr
ID: 6844971
Make it read

printf("cpu= %f",((double) clock())/CLOCKS_PER_SEC);
0
 
LVL 86

Expert Comment

by:jkr
ID: 6844977
FYI, the way you did it, you're doing an integer division. So, if clock() < CLOCKS_PER_SEC, the result is '0'...
0
 

Author Comment

by:anothercto
ID: 6845006
actually I did use the 'double' cast. what really happens is that when I run the program, one out of 4 times, I get cpu=0.015, I get cpu= 0 the other 3 times..
0
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 1

Expert Comment

by:madface
ID: 6845007
clock()/CLOCKS_PER_SEC just shows how long your your app has been running in seconds
0
 
LVL 1

Expert Comment

by:madface
ID: 6845010
clock()/CLOCKS_PER_SEC just shows how long your your app has been running in seconds
0
 
LVL 1

Expert Comment

by:madface
ID: 6845023
so 0 means the application executed really  fast
through  a  in a 6000000 empty loops in your app and see how long it  take
0
 

Author Comment

by:anothercto
ID: 6845034
and most of the times my program takes 0 micro seconds to run? (sometimes 1500 micro seconds.)
0
 
LVL 1

Accepted Solution

by:
madface earned 50 total points
ID: 6845046
so 0 means the application executed really  fast
through  a  in a 6000000 empty loops in your app and see how long it  take
0
 
LVL 1

Expert Comment

by:madface
ID: 6845078
the best way to show you is to break in to the debugger.
wait a while
and execute  the printf statement
it should be a larger number



clock() returns how many ticks  have  elapsed  since you  started  the  app

CLOCKS_PER_SECOND is how many ticks there are in a sec

you get  it
0
 
LVL 1

Expert Comment

by:madface
ID: 6845102
try this  code


void
main()
     {

     long i = 0;

     while(i < 60000000)
          {
          i++;
          }
     
     float cl = clock();
     float val = cl/CLOCKS_PER_SEC;
     printf("cpu= %f",val);

     }
0
 

Expert Comment

by:dchan_4544
ID: 6845175
Actually, clock() reports CPU time USED, which means how much CPU your program actually uses.  So, if your program is not doing much at all, the number you'll get from clock()/CLOCKS_PER_SEC will be very small (very close to 0).  To see a difference, you may be able to do something more complex in a loop like doing bunch of if's or something.  Good luck.

0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
How can i compile this github project?? 2 102
trigs fail! I thought I knew how to do trignometry 3 92
Indy 10 not Receiving UDP broadcast 3 54
Finding Divisors 5 60
When writing generic code, using template meta-programming techniques, it is sometimes useful to know if a type is convertible to another type. A good example of when this might be is if you are writing diagnostic instrumentation for code to generat…
This article shows you how to optimize memory allocations in C++ using placement new. Applicable especially to usecases dealing with creation of large number of objects. A brief on problem: Lets take example problem for simplicity: - I have a G…
The viewer will learn how to pass data into a function in C++. This is one step further in using functions. Instead of only printing text onto the console, the function will be able to perform calculations with argumentents given by the user.
The viewer will learn how to user default arguments when defining functions. This method of defining functions will be contrasted with the non-default-argument of defining functions.

739 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question