There aren't many programs that can be destributed as an exe file alone. Most have various types of data files. Also in many cases, the user will want settings or other data saved for future use. It is very important for our programs to have the ability to interact with other files. There are two types of disk files which we will be working with.
Text files contain lines of text.
A file with a .txt extension is a text file. It is simple characters. But txt is not the only one. html and many word processor formats are stored in text format. This allows it to easily be edited in programs such as notepad.exe. Binary files have no real limitations.