How to measure the running time of a program ?

[andre104]

In UNIX/UNIX-like OSes, you can use the time command.

I'm trying to implement that in Windows, and my first quick attempt this :

Code: [Select]

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>

int main(int argc, char *argv[]){
clock_t start,end;
int x;
char command[100];

if (argc > 1){

for (int x = 1; x < argc; x++){
strcat(command,argv[x]);
strcat(command," ");
}

start = clock();
system(command);
printf("%f\n",(end-start)/CLOCKS_PER_SEC);
end = clock();
}
return 0;

}

The last output is always "0.0000", which means the execution time is not captured properly.
How can I fix that ? Maybe some Win32 API needed ?

[TimoVJL]

Code: [Select]

...
start = clock();
system(command);
end = clock();
printf("%f\n",(float)(end-start)/CLOCKS_PER_SEC);
...

[severach]

GetTickCount() works great for me.

[andre104]

Ah, silly mistake 

I made some workarounds, and the code works :

timeit.c

Code: [Select]

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>

int main(int argc, char *argv[]){
clock_t start,end;
int x;
char command[100];

if (argc > 1){
strcpy(command," ");

for (x = 1; x < argc; x++){
strcat(command,argv[x]);
strcat(command," ");
}

start = clock();
system(command);
end = clock();
printf("%f\n",(float)(end-start)/CLOCKS_PER_SEC);
}
return 0;
}

Now if I invoke the program, e.g :
timeit python matrixmultiplication.py 10, it will print the number estimated to be the running time

But i think system() has overhead
Any better solution ?

[AlexN]

But i think system() has overhead
Any better solution ?

I have an old program, that i found many years ago and which i ported to Pelles C. It starts other programs without system. Perhaps it is a better solution, perhaps not - look at it. ;-)

[pgoh]

But i think system() has overhead
Any better solution ?

The overhead to system() is so small that you shouldn't really care about it. Unless you're timing operations that are so trivial they execute faster than a call to system.