Bench testing a C program

[steve_rm]

Hello

I wondering is there anyway of bench testing a C program. Is there any bench testing software that can be used to test your c programs, as l want compare some programs l have written to find out which one executes fastest.

Many thanks in advance

[parksie]

What compiler and OS are you using? Visual C++ has a profiler, and GCC has gprof for the same tool.

Under Unix, you can also use the 'time' command to see how long a program took to execute.

[steve_rm]

I am using window ME and the compilers l am using are Visual C++ 6 and borlands 4.5.

Can you give me any instructions on how to use the bench testing, in either of these compilers.

Many thanks in advance

[parksie]

You can't really "bench test" a program. If you look up the profiler in the MSVC documentation, it tells you how to find which functions get called the most, and how long is spent in each function.

This allows you to intelligently choose which functions to optimise.

[jim mcnamara]

You can write a 'workbench' or instrumentation app.

Basically what you do:

Loop for each compiled .exe file
       call GetTickCount - or another higher resolution timer
       call CreateProcess to run the exe
       call WaitForSingleObject using the process handle
       call GetTickCount to find the elapsed time.
       Display file name, elapsed time.
end loop

When you run this type of code make sure there isn't anything running in background.

[jim mcnamara]

As an addend:

Performance testing is what you normally call what you want, I believe.

Profiling, as Parksie mentioned, is a great way to find code bottlenecks.

Other kinds of testing are:

unit testing - a programmer verifying the correctness and completeness of code

QA - standardized testing for correctness, error handling, data input control & verification, data output control & verification.
This means you subject the program to all kinds of abuse, as well as planned stupidity on the part of the user. For example, Blizzard tested DiabloII in house, then released a thousand beta copies to avid 14 year olds. They found nearly a hundred problems in matter of a few days. Then they opened up Battle.net to similar testing and found a load more.