title: How to convert long string number value into integer
body: <p>what I have to use instead <code>ToInt32</code>, to convert long string number value "10000000001" into integer, so this way is limited to a ten-digit number: </p>
  
  <pre><code>    string str1 = "1000000000";
      string str2 = "1000000000";
  
      int a = Convert.ToInt32(str1);
      int b = Convert.ToInt32(str2);
  
      int c = a + b;
  
      Console.WriteLine(c);
  </code></pre>
  
  <p>result: </p>
  
  <pre><code>2000000000
  </code></pre>
  
  <p>but how to convert if string number value is larger then ten-digit number: </p>
  
  <pre><code>    string str1 = "10000000001";
      string str2 = "10000000001";
  </code></pre>
  
  <p>to get result:</p>
  
  <pre><code>20000000002
  </code></pre>