title: Iterating through List of Strings C#
body: <p>I need to build a string by iterating through list of strings</p>
  
  <p>my input is a  <code>List&lt;string&gt;</code> and below are 3 sample cases of possible input:</p>
  
  <pre><code>case 1        case2      case3
    5             5          ""
    +             +          +
    6             6          6
    +             +          +
    9             9          9
    -             -          -
    8             ""         8
    +             +          +
    1             1          1
  </code></pre>
  
  <p>The desired resulting output for each of the above sample cases should be as follows (each of which is a single string value):</p>
  
  <p>Case1 : <code>"5+6+9-8+1"</code></p>
  
  <p>Case2 : <code>"5+6+9+1"</code>  (as the value after 9 is "" it shouldn't be considered and the preceding operator should also be ignored)</p>
  
  <p>Case3 : <code>"6+9-8+1"</code>  (as first value is "" it shouldn't be considered it and following operator should also be ignored)</p>