When you have a sequence of commands to perform repeatedly or that you want to save for future reference, store them in a program file. The simplest type of MATLAB^® program is a script, which contains a set of commands exactly as you would type them at the command line. For additional programming flexibility, create functions which accept input and return outputs. When you have specialized data structures or require many functions to interact with special kinds of data, create classes using object-oriented programming techniques.