About CPU time

[haaaz]

How can I know how long my program runs?
Do I have to code myself or I can get such information from my compiler.......?

And how about the memory size a program uses?

[kmhasan]

If you're using linux it's trivial, you don't need to do add anything in the code. Given a binary executable a.out and an input file a.in you can use:

Code: Select all

time ./a.out < a.in

For platform independence, I think you can use the functions provided in time.h.
[cpp]
#include <time.h>
#include <stdio.h>

int main() {
clock_t start = clock();
/* do whatever is needed */
clock_t stop = clock();
printf("%.3lfs\n",(double)(stop-start)/CLOCKS_PER_SEC);
return 0;
}
[/cpp]

[haaaz]

How about memory usage?

[anupam]

well problemsetter bhai, thanks for your great teaching.
it's very important use.
will it work on cygwin?
will there be any problem to judge if i use clock_t will it return compile error?
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[ec3_limz]

well problemsetter bhai, thanks for your great teaching.
it's very important use.
will it work on cygwin?
will there be any problem to judge if i use clock_t will it return compile error?

I think the functions in time.h are available for any compiler. However, I don't see any point in sending a program using the time functions to the judge.

[anupam]

well a great important question is abt memory usage.
this is bcz it is not possible to calculate total memory from all the variable list whn using a big program.
and many dos compiler don't allow a fixed limit of memory.
so how many variables to allocate in the given menmory is a big ?.
--
if any1 knows please let us know abt it..