title: SWIFT Variable used before being initialized
body: <p>I want to know why this code will not run. The error appears on the very last line (the print statement) (the last "letter grade") and says </p>
  
  <blockquote>
    <p>"Variable 'letterGrade' used before being initialized"</p>
  </blockquote>
  
  <pre><code>let score = 86
  var letterGrade: Character
  
  if(score &gt;= 90)
  {
      letterGrade = "A"
  }
  else if(score &gt;= 80)
  {
      letterGrade = "C"
  }
  else if (score &gt;= 70)
  {
      letterGrade = "C"
  }
  else if (score &gt;= 60)
  {
      letterGrade = "D"
  }
  else if (score &gt; 0)
  {
      letterGrade = "F"
  }
  print("Your letter grade is \(letterGrade)")
  </code></pre>