Timing homework

Question

Last week our class was given the folllowing instructions to do a program:

o   Input range of N values

o   Create range_time_vector

o   Input number_of_cases

o   for each input in the range of inputs

·         Set time_sum to zero

·         Set time_average to zero

·         For each case

§  Start the time

§  Execute the loop

§  End the time

§  Add the time difference to time_sum

o   Calculate time_average = time_sum/ number_of_cases

o   Store time_average in range_time_vector at input index

So far I've been able to do this much:

#include <iostream>
#include <vector>

using namespace std;

int main ()
{
      int N =0;
      int Range=0;
      int NumberOfCases=0;
      cout << "Enter N" <<endl;
      cin >> N;
      cout << "Enter Range" <<endl;
      cin >> Range;
      cout << "Number of cases" <<endl;
      cin >> NumberOfCases;
      vector<double> range_time_Vector(Range);
      int K = N;
      for(int i=0; i < Range; ++i)
      {
          double time_sum = 0.0;
          double time_average = 0.0;
          for (int m=1 ; m <= NumberOfCases; ++m)
          {
             cout << "for m=" << m << "  K=" << K << endl;
          }
      }
      return 0;
}

Can Someone help me with the following steps:
For each case

§  Start the time

§  Execute the loop

§  End the time

§  Add the time difference to time_sum

o   Calculate time_average = time_sum/ number_of_cases

o   Store time_average in range_time_vector at input index

I tried googling and going to cplusplus.com, but wasn't able to find anything to help me with my program.

Answer 1

> Can Someone help me with the following steps:

These forums aren't really for homework assignments, however here's some
hints that may get you a bit futher ;)

> § Start the time

I'd replace the above with "get the current time" (and save it)

> § End the time

Get the time now.

Dave

Answer 2

Well, to calculate time, you have a couple of options.  std::clock() can be used to get "ticks" that have elapsed since your program began.  The resolution may not be what you need.  You get CLOCKS_PER_SEC "ticks" every second (this is 1000 in VS2008).

If you want to use Microsoft specific code, try QueryPerformamceCounter and QueryPerformanceFrequency for high-precision timing.