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POInsert an underlying value into a non-existing index
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  1. POInsert an underlying value into a non-existing index
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    copied!<p>I'm trying to solve a simple algorithm a specific way where it takes the current row and adds it to the top most row. I know there are plenty of ways to solve this but currently I have a text file that gets read line by line. Each line is converted to an sbyte (there's a certain reason why I am using sbyte but it's irrelevant to my post and I won't mention it here) and added to a list. From there, the line is reversed and added to another list. Here's the code I have for that first part:</p> <pre><code> List&lt;List&lt;sbyte&gt;&gt; largeNumbers = new List&lt;List&lt;sbyte&gt;&gt;(); List&lt;string&gt; total = new List&lt;string&gt;(); string bigIntFile = @"C:\Users\Justin\Documents\BigNumbers.txt"; string result; StreamReader streamReader = new StreamReader(bigIntFile); while ((result = streamReader.ReadLine()) != null) { List&lt;sbyte&gt; largeNumber = new List&lt;sbyte&gt;(); for (int i = 0; i &lt; result.Length; i++) { sbyte singleConvertedDigit = Convert.ToSByte(result.Substring(i, 1)); largeNumber.Add(singleConvertedDigit); } largeNumber.Reverse(); largeNumbers.Add(largeNumber); } </code></pre> <p>From there, I want to use an empty list that stores strings which I will be using later for adding my numbers. However, I want to be able to add numbers to this new list named "total". The numbers I'll be adding to it are not all the same length and because so, I need to check if an index exists at a certain location, if it does I'll be adding the value I'm looking at to the number that resides in that index, if not, I need to create that index and set it's value to 0. In trying to do so, I keep getting an IndexOutOfRange exception (obviously because that index doesn't exist). :</p> <pre><code> foreach (var largeNumber in largeNumbers) { int totalIndex = 0; foreach (var digit in largeNumber) { if (total.Count == 0) { total[totalIndex] = digit.ToString(); //Index out of Range exception occurs here } else { total[totalIndex] = (Convert.ToSByte(total[totalIndex]) + digit).ToString(); } totalIndex ++; } } </code></pre> <p>I'm just at a loss. Any Ideas on how to check if that index exists; if it does not create it and set it's underlying value equal to 0? This is just a fun exercise for me but I am hitting a brick wall with this lovely index portion. I've tried to use SingleOrDefault as well as ElementAtOrDefault but they don't seem to be working so hot for me. Thanks in advance!</p>
 

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