title: About Use of #include Preprocessor Directive in C++
body: <p>I stumble on the following compilation error in C++ with g++ compiler:</p>
  
  <pre><code>error on line line 1 with message:
  invalid preprocessing directive #a
  </code></pre>
  
  <p>(with a caret above the character a) which is followed by another,probably consequent, error on line 4 with message:</p>
  
  <pre><code>cout was not declared in this scope. 
  </code></pre>
  
  <p>The editor i am using is Code blocks 10.05 with mingw.I tried removing .h extension from the iostream file include statement;switching among different File encoding options;and replacing the angular bracket with single quotes and double quotes as well.i am stuck on it.Pardon if it is a duplicate(although i went through several already asked questions in relevance).
      The following code illustrates the problem:</p>
  
  <pre><code>#‪include ‬&lt;iostream.h&gt;
  int main()
  {
  cout&lt;&lt; "abc"+8;
  cout&lt;&lt; "def"+4;
  cout&lt;&lt; "ha";
  return 0;
  }
  </code></pre>