Get the running time of a function in c++

Question

I want to calculate the running time of a function for my assignment. I keep getting 0 nut my teacher strictly said that he want some non zero value even for a loop of 10 size. My code so far is this

#include <chrono>

using namespace std;
using std::chrono::duration_cast;
using std::chrono::nanoseconds;
using std::chrono::steady_clock;

steady_clock::time_point t1 = steady_clock::now();
for(int i=0;i<times;i++){
    bubbleSort(arr,size);
}
steady_clock::time_point t2 = steady_clock::now();
cout<<(float)duration_cast<nanoseconds>(t2-t1).count()/times<<"     ";

i have also tried chrono::high_resolution_clock , clock() and many others. The main problem is that i have to give some non zero value for time=1; and size=10. Please suggest how could i do this?

You cannot measure times that are less than a clock resolution. — Alex Telishev, Feb 05 '14 at 20:47
What Alex said, also try `high_resolution_clock` in case `steady_clock` is not very high resolution in your OS. — vanza, Feb 05 '14 at 20:49
There is a nested loop in the `bubbleSort` function. Even a simple `cout<<"Hello Worl\n";` gives some non zero value. I don't understand how cout takes more time than nested loop and a check condition — SSMA, Feb 05 '14 at 20:51
time taken to execute a complete function http://stackoverflow.com/a/40380118/6180077 — Abdullah Farweez, May 17 '17 at 05:06

score 0 · Accepted Answer · answered Feb 05 '14 at 20:59

0

I tried running your code, commenting the bubbleSort part of course. It is giving some non zero value. Try this :

cout<<(float)duration_cast<nanoseconds>(t2-t1).count()/(float)times<<"     ";

answered Feb 05 '14 at 20:59

Wajahat

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@SSMA What compiler are you using? Is it Visual Studio? – David G Feb 05 '14 at 21:03
Yes Visual Studio 2012 – SSMA Feb 05 '14 at 21:05
1

@SSMA , try running your code at http://www.compileonline.com/compile_cpp11_online.php – Wajahat Feb 05 '14 at 21:05
@SSMA Visual Studio has problems with the C++11 date and time facilitates. There was a question posted about a year ago from someone with the same problem but I can't find it at the moment. – David G Feb 05 '14 at 21:07
@Wajahat thanks for your suggestion. It worked on compileonline.com. But is there a way to make it work on visual studio? – SSMA Feb 05 '14 at 21:32
Why do you really need to run it on visual studio, as @0x499602D2 said there are problems with it. – Wajahat Feb 05 '14 at 21:35
@SSMA Repeating what Wajahat asked, why do you need to run it on Visual Studio? – David G Feb 05 '14 at 21:50
@Wajahat I have to submit an exe file not the code. I can only create the exe through visual studio. – SSMA Feb 06 '14 at 11:07
@0x499602D2 I have to submit an exe file not the code. I can only create the exe through visual studio. – SSMA Feb 06 '14 at 11:08
I think you can create an exe in other ways also, compilation actually converts it into an executable. Here is a link: http://stackoverflow.com/questions/8450121/how-do-i-create-a-exe-from-a-cpp-file-in-code-blocks – Wajahat Feb 06 '14 at 11:26

Get the running time of a function in c++

1 Answers1