Implementation of the Timer class in the programming language С++.

Timer.h

#pragma once

#include <stdio.h>
#include <time.h>


void StartTimer(void);

double StopTimer(void);

double PrintTimer(void);



#if defined(__WIN32__) || defined(_WIN32)
#include <Windows.h>
DWORD m_start, m_end;
#else
#include <sys/time.h>
struct timeval	m_start, m_end;
#endif


void StartTimer(void)
{
#if defined(__WIN32__) || defined(_WIN32)
	m_start = GetTickCount();
#else
	if (gettimeofday(&m_start, 0)) fprintf(stderr, "cant get time!\n");
#endif
}

double StopTimer(void)
{
#if defined(__WIN32__) || defined(_WIN32)
	m_end = GetTickCount();
	return m_start - m_end;
#else
	if (gettimeofday(&tve, 0)) fprintf(stderr, "cant get time!\n");
	return 1000 * (m_end.tv_sec - m_start.tv_sec + (double)(m_end.tv_usec - m_start.tv_usec) / 1000000.0);
#endif
}

double PrintTimer(void)
{
	double duration;

#if defined(__WIN32__) || defined(_WIN32)
	m_end = GetTickCount();
	//t = (double)(m_end - tvs) / 1000.0; // seconds 
	duration = (double)(m_end - m_start); // ms
	printf("%.3f ", duration);
	return duration;
#else
	if (gettimeofday(&tve, 0)) fprintf(stderr, "cant get time!\n");
	duration = 1000 * (tve.tv_sec - tvs.tv_sec + (double)(tve.tv_usec - tvs.tv_usec) / 1000000.0);
	printf("%.3f ", duration);
	return duration;
#endif
}

timer_chrono.h

#include <iostream>
#include <chrono>
#include <thread>
#include <string>

#include "APTimer.h"

#define Name "Alex Povod"

struct Timer
{
    std::chrono::time_point<std::chrono::steady_clock> start, end;
    std::chrono::duration<float> duration;

    Timer()
    {
        start = std::chrono::high_resolution_clock::now();
    }

    ~Timer()
    {
        end = std::chrono::high_resolution_clock::now();
        duration = end - start;

        float ms = duration.count() * 1000.0f;
        std::cout << "Timer took " << ms << "ms" << std::endl;
    }
};


void Entity()
{
    Timer timer;

    auto i = 0;
    StartTimer();
    do { std::cout << "Hello " << Name << std::endl;
    i++;
    } while (i < 100);
    StopTimer();
    PrintTimer();
}

int main()  
{
#if 0
    using namespace std::literals::chrono_literals;

    auto start = std::chrono::high_resolution_clock::now();
    std::this_thread::sleep_for(1s);
    auto end = std::chrono::high_resolution_clock::now();

    std::chrono::duration<float> duration = end - start;
    std::cout << duration.count() << "s " << std::endl;

#endif

    Entity();

    std::cin.get();

}