title: Not sure how to exclude number values from my output
body: <p>using C++ I have made this code to determine when a user inputs a value if it is an upper case or lowercase value or not a value at all that part is easy for me and I have additionally made it so the output will also  convert a lowercase input into an uppercase input and an uppercase input into a lowercase input my proffesort has only allowed us to use if else statments meaning no arrays or vectors and I am not sure how to exclude my code from converting if it is a number value I am totally lost in using this ascii table. Please help Below is my code</p>
  
  <pre><code>#include &lt;iostream&gt;
  using namespace std;
  int main()
  {
  char Letter; //defines the char variable letter for the user to input a value
  
  cout&lt;&lt; "Please input a letter :)!" &lt;&lt; endl;
  cin&gt;&gt; Letter;
  
      if ( Letter&gt;= 65 &amp;&amp; Letter &lt;= 90) //checks the acsii dec values to see if the input is a
          cout&lt;&lt; "This is an uppercase letter!"&lt;&lt;endl;//lowercase letter
  else  if (Letter &gt;= 97 &amp;&amp; Letter &lt;= 122)//checks to see if the acsii dec value is 
            cout&lt;&lt; "This is a lower case letter!"&lt;&lt;endl;//uppercase
        else 
            cout&lt;&lt;"This is not a letter :("&lt;&lt;endl;//outputs this if the acsii value is not a letter
  
  if (Letter &gt;=65&amp;&amp; Letter &lt;= 90)
  {
      Letter+=32;
      cout&lt;&lt; Letter&lt;&lt;" "&lt;&lt;"This is the Lowercase of your uppercase letter!\n";
  }
  else  (Letter &gt;= 97 &amp;&amp; Letter &lt;=122);
  {
      Letter-=32;
      cout&lt;&lt; Letter&lt;&lt;" "&lt;&lt;"This is the Uppercase of your lowercase letter!\n";
  }
  
  system("pause");
  return 0;
  </code></pre>