# Using timers to measure execution time

In this example we are using the Real_Timer class to measure the execution time of a simple program. The Real_Timer class is included in the itmisc library.

    #include <itpp/itbase.h>

    using namespace itpp;

    //These lines are needed for use of cout and endl
    using std::cout;
    using std::endl;

    int main()
    {
      //Declare the scalars used:
      long i, sum, N;

      //Declare tt as an instance of the timer class:
      Real_Timer tt;

      //Initiate the variables:
      N = 1000000;
      sum = 0;

      //Start and reset the timer:
      tt.tic();

      //Do some processing
      for (i = 0; i < N; i++) {
        sum += i;
      }

      // Print the elapsed time
      tt.toc_print();

      //Print the result of the processing:
      cout << "The sum of all integers from 0 to " << N - 1 << " equals " << sum << endl;

      //Exit program:
      return 0;

    }

When you run this program, the output will look something like this:

    Elapsed time = 0.000797055 seconds
    The sum of all integers from 0 to 999999 equals 1783293664