While all this gives you a refresher of the data structures we will be working on, in real life, instead of inventing data, we read it from data sources. A tab-delimited plaintext file is the simplest and most common type of data input. Imagine we have a file called evens.txt containing the aforementioned even numbers. There are two columns. The first column only records unnecessary information. We want to load the data in the second column.

Here is what the dummy text file looks like: