Timing sorting algorithms

[4ET0pfjN]

Hi, I need to time sorting algorithms that I wrote, I wonder if there is better way to go more accurate like 2 decimal places, this is what I have so far.

#include <ctime>
#include <iostream>
using namespace std;

int main()
{
	clock_t startTime = clock();
	int arraySize = 100000; 
	int *insertionList = createArray(arraySize);
	
	//sort this list
	insertionSort(insertionList, arraySize);//my insertion sort fcn
	
	clock_t endTime = clock();
	clock_t duration = (endTime - startTime)/CLOCKS_PER_SEC;
	cout<<"Elapsed time: "<<duration*1000<<" ms"<<endl;

	return 0;
}

I'm getting 11000 ms, the reason I ask is b/c I need to compare the running time for my own implementation of the classic sorting algorithms.

[Athar]

You're performing integer division, so make sure you use floating point numbers throughout, e.g.

clock_t duration = double(endTime - startTime)/CLOCKS_PER_SEC*1000;
cout << "Elapsed time: " << duration << " ms" << endl;

[roberts]

There is a high resolution timer on most modern PCs.

If you're developing on Windows, look at GetPerformanceFrequency and GetPerformanceCounter.

I don't know if linux/unix has anything similar.

[Athar]

It's QueryPerformanceFrequency and QueryPerformanceCounter.
On Unices, there's clock_gettime() for high resolution measurements.

However, if milliseconds are not sufficient, then you're usually better off repeating your function for a few thousand/million times, which usually leads to far more accurate results.

[roberts]

Sorry about getting the names wrong. It's been a while since I pulled them up and was working off memory(obviously mine has a leak).