title: Issue C1083: cannot open include file: 'chrono': no such file or directory pops out
body: <p>I'm trying to make a program that makes 6 numbers come out randomly.</p>
  
  <p>This is my .pro file</p>
  
  <pre><code>QT       += core gui
  
  greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
  
  TARGET = Lotto
  TEMPLATE = app
  
  CONFIG += c++11
  
  SOURCES += main.cpp\
          mainwindow.cpp \
      lottogenerator.cpp
  
  HEADERS  += mainwindow.h \
      lottogenerator.h
  
  FORMS    += mainwindow.ui
  </code></pre>
  
  <p>This is my .h file</p>
  
  <pre><code>#ifndef LOTTOGENERATOR_H
  #define LOTTOGENERATOR_H
  
  
  #include &lt;string&gt;
  #include &lt;random&gt;
  #include &lt;array&gt;
  #include &lt;chrono&gt;
  
  class LottoGenerator
  {
  public:
      typedef std::chrono::high_resolution_clock myclock;
  
      LottoGenerator();
  
      std::array&lt;int, 6&gt; get();
  
  private:
      int rand();
  
      std::mt19937 *engine;
      std::uniform_int_distribution&lt;int&gt; distribution;
  
      myclock::time_point beginning = myclock::now();
  };
  
  #endif // LOTTOGENERATOR_H
  </code></pre>
  
  <p>This is my .cpp file.</p>
  
  <pre><code>#include "lottogenerator.h"
  
  LottoGenerator::LottoGenerator()
      : distribution(1,45)
  {
      myclock::duration d = myclock::now() - beginning;
      unsigned int seed = d.count();
  
      engine.seed(seed);
  }
  
  std::array&lt;int, 6&gt; LottoGenerator::get()
  {
      std::array&lt;int, 6&gt; numbers;
  
      numbers[0] = rand();
      numbers[1] = rand();
      numbers[2] = rand();
      numbers[3] = rand();
      numbers[4] = rand();
      numbers[5] = rand();
  
      return numbers;
  }
  
  int LottoGenerator::rand()
  {
      return distribution(engine);
  }
  </code></pre>
  
  <p>and when I run, "C1083: cannot open include file: 'chrono': no such file or directory" pops out.</p>
  
  <p>It would be grateful if you could help:) </p>