# 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