title: What does it mean if a "variable or field" is declared void? Error message help
body: <p>variable or field `letterGrade' declared void. This error message is coming up on the last iteration of the function 'letterGrade'. Anyone have an idea why? </p>
  
  <pre><code>#include &lt;string&gt;
  #include &lt;iostream&gt;
  using namespace std;
  void letterGrade (int score, string&amp; scoreLetter);
  string scoreLetter;
  int main()
  {
      int score;
      char A, B, C, D, F;
      cout&lt;&lt;"Enter the grade: ";
      cin&gt;&gt; score;
      letterGrade (score, scoreLetter);
      cout&lt;&lt;"The letter grade is a(n) "&lt;&lt; scoreLetter&lt;&lt;".";
      system ("pause");
      return 0;
  }
  void letterGrade (score, scoreLetter)
  {
       for (score &gt;= 90)
       {
               scoreLetter = 'A';}
        if (score == 100)
       {
               scoreLetter.insert (1, "+");
       } 
       else if (8&lt;=score% 10 &amp;&amp; score% 10 &lt;= 9)
       {
                     scoreLetter.insert (1, "+");
       else if (0&lt;=score% 10 &amp;&amp; score% 10 &lt;=1)
       {
                     scoreLetter.insert (1, "-");
       } 
  </code></pre>