Timer class - Time how long your programs run for

//
// example.cpp : Shows example ways in which the timer class can be used. File is also used as an
// unit test of the object. Application is CLI based.
//
// Notes: This program uses the Sleep() function in windows.h to pause the application for certain
// periods of time, which tends not to be incredibly accurate. This means that times may be off by
// a few milliseconds when computing.
//
// This example program has been compiled successfully with "Microsoft Visual Studio .NET 2003,"
// "Microsoft Visual Studio 2005," and "Dev-C++" under the windows operating systems. This
// application has not been tested with any other compilers.
//
// Made by: Robert Roose
//          summatix
//

#include <iostream>
#include <string>
#include <windows.h> //windows.h is used for its Sleep() function
#include <sstream>
#include "timer.h" //Include the timer class

using namespace std;

int main()
{
    //Start of application
    //
    //Start of Test 1
    //
    cout << "Test 1\n" << "============" << endl;
    timer timerA; //Create a new timer instance
    cout << "Starting the Timer...\n";
    timerA.start(); //Start the timer
    cout << "Pausing the program for 2 seconds...\n";
    Sleep(2000); //Pause the application for 2 seconds
    timerA.stop(); //Stop the timer
    cout << "Timer Stopped\n";

    //Output how long the timer instance has been running
    cout << "The application has been running for: " << timerA << "\n";
    cout << "The output should have been: 2secs\n";

    cout << "Test 1 finished\n\n" << endl;
    //
    //End of Test 1

    //Start of Test 2
    //
    cout << "Test 2\n" << "============" << endl;
    cout << "Starting the timer again, and then pausing for 2.5 seconds\n";
    timerA.start(); //Start the timer again
    Sleep(2500); //Pause the application for 2.5 seconds
    timerA.stop(); //Stop the timer
    cout << "Timer Stopped\n";

    //Output how long the timer instance has been running
    cout << "The application has been running for: " << timerA << "\n";
    cout << "The output should have been: 4.5secs\n";

    cout << "Test 2 finished\n\n" << endl;
    //
    //End of Test 2

    //Start of Test 3
    //
    cout << "Test 3\n" << "============" << endl;
    cout << "Restarting the timer, and then pausing for 1.515 seconds\n";
    timerA.restart(); //Restart the timer
    Sleep(1515); //Pause the application for 1.523 seconds
    timerA.stop(); //Stop the timer
    cout << "Timer Stopped\n";

    //Output how long the timer instance has been running
    cout << "The application has been running for: " << timerA << "\n";
    cout << "The output should have been: 1.515secs\n";

    //Store the running length of the timer instance as a string type
    string testString = timerA;
    cout << "Outputting string\n";

    //Output how long the timer instance has been running
    cout << "The application has been running for: " << testString << "\n";
    cout << "The output should have been: 1.515secs\n";

    //Store the number of seconds the timer has been running for in an int data type
    int testInt = timerA;
    cout << "Outputting int\n";

    //Output how long the timer instance has been running
    cout << "The application has been running for: " << testInt << "\n";
    cout << "The output should have been: 1\n";

    //Store the number of seconds the timer has been running for in a double data type
    double testDouble = timerA;
    cout << "Outputting double\n";
 
    //Output how long the timer instance has been running
    cout << "The application has been running for: " << testDouble << "\n";
    cout << "The output should have been: 1.515\n";

    cout << "Test 3 finished\n\n" << endl;
    //
    //End of Test 3

    //Start of Test 4
    //
    cout << "Test 4\n" << "============" << endl;
    cout << "Creating a new timer, starting instantly, and then pausing for 1 hour, 23 minutes,"
         << " and 6 seconds.\n";

    timer timerB(true); //Create a new timer, starting instantly
    Sleep(4986000); //Pause application for 1 hour, 23 minutes and 6 seconds
    timerB.stop(); //Stop the timer

    timerB.setClockType(cpuClock); //Set the timer to use the cpu clock

    //Output how long the timer instance has been running using the cpu clock
    cout << "Using cpu clock, the application has been running for: " << timerB << "\n";
    cout << "The output should have been: 1hr 23mins 6secs\n";

    timerB.setClockType(systemClock); //Set the timer to use the system clock

    //Output how long the timer instance has been running using the systen clock
    cout << "Using system clock, the application has been running for: " << timerB << "\n";
    cout << "The output should have been: 1hr 23mins 6secs\n";

    cout << "Test 4 finished\n\n" << endl;
    //
    //End of Test 4*/

    //
    //End of application

    system("PAUSE");
    return 0;
}