title: Method without parenthises in C++
body: <p>So I'm currently writing a C++ OpenGL program and I'm fairly new in the language.
  What is a method called that has no parenthises?</p>
  
  <p>My code block:</p>
  
  <p>Program.cpp:</p>
  
  <pre><code>Input input;
  
  glfwSetKeyCallback(window, input.HandleInput); //On this line input.HandleInput is the question at hand
  </code></pre>
  
  <p>Input.h</p>
  
  <pre><code>class Input
  {
  public:
      void HandleInput(GLFWwindow* window, int key, int scancode, int action, int mods);
  private:
  };
  </code></pre>
  
  <p>Input.cpp</p>
  
  <pre><code>#include &lt;GL/glew.h&gt;
  #include &lt;GLFW/glfw3.h&gt;
  
  #include &lt;iostream&gt;
  
  #include "Input.h"
  
  void Input::HandleInput(GLFWwindow* window, int key, int scancode, int action, int mods)
  {
  
       if (key == GLFW_KEY_F &amp;&amp; action == GLFW_PRESS)
       {
           std::cout &lt;&lt; key &lt;&lt; " pressed.";
       }
  
  }
  </code></pre>
  
  <p>Also i'd appreciate it if someonw would tell me how i could correctly execute the input.HandleInput method.</p>