how to know the time taken to complete a program?

[RajuRaman]

I want to know how we can calculate the time taken for the compilation of a program...pls help..

[Ganon11]

Check out this function.

[sicarie]

Check out this function.

You know how to tell when you're too tired to be at work? You look at the URL and think, "What the hell is the C Lock function?" And realize only by noticing 'ctime' that it's "clock".

Okay, let's see if I can get away with sleeping in my cube.

[RajuRaman]

Check out this function.

Actually i want to know the compilation time of a c++ program...could u pls tell me how can i use the function clock....

[r035198x]

Actually i want to know the compilation time of a c++ program...could u pls tell me how can i use the function clock....

Some compilers are kind enough to tell you such details or maybe you are writing a C++ compiler using C++?

[RajuRaman]

Some compilers are kind enough to tell you such details or maybe you are writing a C++ compiler using C++?

Ya I am writing a C++ program...and i tried the below program


#include<time.h>
#include<stdio.h>
#include<dos.h>
int main(void)
{
clock_t start , end;
start=clock();
delay(2000);
end= clock();
printf("the time was: %f \n",(end-start/CLK_TCK_;
return 0;
}

but this doesnt give the proper time..its giving the time after i press RUN..

[Banfa]

What's your interest in knowing the compilation/link time?

The only times when it has ever been an issue in my carrier it has been acceptable to time it by hand using a trust wrist watch and just noting the approximate start and end times, i.e. normally people only care when the time is long enough to measure inaccurately with knowing the exact start and stop times.

[r035198x]

Ya I am writing a C++ program...and i tried the below program


#include<time.h>
#include<stdio.h>
#include<dos.h>
int main(void)
{
clock_t start , end;
start=clock();
delay(2000);
end= clock();
printf("the time was: %f \n",(end-start/CLK_TCK_;
return 0;
}

but this doesnt give the proper time..its giving the time after i press RUN..

1.) Use code tags when posting code
2.) That won't give you compilation time. Compilation time by the way will be different on different compilers and platforms. You need to give a C++ source file as an argument to a compiler that you have access to so that you then measure the start and stop time of the compilation process that you will have manually started.

[RajuRaman]

What's your interest in knowing the compilation/link time?

The only times when it has ever been an issue in my carrier it has been acceptable to time it by hand using a trust wrist watch and just noting the approximate start and end times, i.e. normally people only care when the time is long enough to measure inaccurately with knowing the exact start and stop times.

My interest is that..I hav 2 C++ programs....and I want to know which one will take less time...and choose the best between the two...and the time is in milli seconds..which cannot b noted using a wrist watch..

[r035198x]

What's your interest in knowing the compilation/link time?

The only times when it has ever been an issue in my carrier it has been acceptable to time it by hand using a trust wrist watch and just noting the approximate start and end times, i.e. normally people only care when the time is long enough to measure inaccurately with knowing the exact start and stop times.

Only use I can think of it is when one is making a C++ compiler wants to test their compiler's compilation speed.
I'm of the opinion that writing a C++ compiler is actually useless in itself so there.

[Banfa]

I'm of the opinion that writing a C++ compiler is actually useless in itself so there.

That rather depends on if you are manufacturing a new processor or not. If you are creating a new processor then not creating a compiler for it is going to somewhat limit it's use :D

[r035198x]

My interest is that..I hav 2 C++ programs....and I want to know which one will take less time...and choose the best between the two...and the time is in milli seconds..which cannot b noted using a wrist watch..

Take a deep breadth.
Now read this:
Compilation time is different from running time.

A fast program is not a program that takes a short time to compile. It is one that takes a short time to run.

[r035198x]

That rather depends on if you are manufacturing a new processor or not. If you are creating a new processor then not creating a compiler for it is going to somewhat limit it's use :D

Thankfully I don't fiddle around with such stuff anymore.
Of course creating a processor is not entirely useless so I take back half of my ealier remark.

[Banfa]

A fast program is not a program that takes a short time to compile. It is one that takes a short time to run.

Actually almost certainly the reverse, optimisation takes far longer than actual compilation of the code so if you where to switch off the optimisation in your compiler you will almost certainly end up with a program that compiles faster.

However optimised code almost always runs faster than un-optimised code so if you switch off the optimiser you will almost certainly end up with a program that runs slower.

[r035198x]

Actually almost certainly the reverse, optimisation takes far longer than actual compilation of the code so if you where to switch off the optimisation in your compiler you will almost certainly end up with a program that compiles faster.

However optimised code almost always runs faster than un-optimised code so if you switch off the optimiser you will almost certainly end up with a program that runs slower.

So how is my comment the reverse of this?

[Banfa]

So how is my comment the reverse of this?

Sorry I meant your statement did not go far enough, a short compile time is likely to mean a long run time and vice versa.