CTimeSpan always gets zero - c++

Question

I am trying to get the running time of Insertion Sort Algorithm. MSDN said that using CTime could get the Elapsed Time. But I tried many times and always got zero. I thought it is impossible that the time of running this algorithm is zero. There must be some error or something else. Could anybody help me? I posted my code below:
#include <cstdlib>
#include <iostream>
#include <atltime.h>
using namespace std;
//member function
void insertion_sort(int arr[], int length);
int *create_array(int arrSize);
int main() {
//Create random array
int arraySize=100;
int *randomArray=new int[arraySize];
int s;
for (s=0;s<arraySize;s++){
randomArray[s]=(rand()%99)+1;
}
CTime startTime = CTime::GetCurrentTime();
int iter;
for (iter=0;iter<1000;iter++){
insertion_sort(randomArray,arraySize);
}
CTime endTime = CTime::GetCurrentTime();
CTimeSpan elapsedTime = endTime - startTime;
double nTMSeconds = elapsedTime.GetTotalSeconds()*1000;
cout<<nTMSeconds;
return 0;
}//end of main

Answer 1

CTime isn't meant to time things to a resolution less than one second. I think what you are really after is something like GetTickCount or GetTickCount64 . See this MSDN link .
GetTickCount function
Retrieves the number of milliseconds that have elapsed since the system was started, up to 49.7 days.
If using GetTickCount64 you could declare startTime and endTime this way:
uint64_t endTime, startTime, diffTime;
Then use GetTickCount64 to retrieve the time in milliseconds with something like
startTime = GetTickCount64();
... do stuff ...
endTime = GetTickCount64();
diffTime = endTime - startTime;
And of course diffTime can be used however you want.
If you don't need to time things for more than a month then you can simply use GetTickCount and the type returned will be a uint32_t instead of uint64_t
If you need resolution beyond 1 millisecond for timing and your computer supports a high resolution timer then this code may work:
LARGE_INTEGER freq;
double time_sec = 0.0;
if (QueryPerformanceFrequency(&freq))
{
LARGE_INTEGER start;
LARGE_INTEGER stop;
QueryPerformanceCounter(&start);
// Do Stuff to time Here
QueryPerformanceCounter(&stop);
time_sec = (uint64_t)(stop.QuadPart - start.QuadPart) / (double)freq.QuadPart;
}
else {
cout << "Your computer doesn't have a high resolution timer to use";
}
Information on the high performance timer can be found in this MSDN entry