You have to mention its name in some respect, so that the operating system will know what file to open. It’s easy to get the name in your script automatically:
txtfile = dir('*.txt');
filename = txtfile.name;
After that, open and read it however you like. It would be easiest if you saved it as a ‘.mat’ file (that could be saved in ASCII format), because you could then simply use the load function and not have to bother with the format. See the documentation on save and load for details.
