Programming and Data Types

Obtaining User Input

There are three ways to obtain input from a user during M-file execution. You can:

• Display a prompt and obtain keyboard input.
• Pause until the user presses a key.
• Build a complete graphical user interface.

This section covers the first two topics. The third topic is discussed in online documentation under Creating Graphical User Interfaces.

Prompting for Keyboard Input

The input function displays a prompt and waits for a user response. Its syntax is

• n = input('prompt_string')
  

The function displays the prompt_string, waits for keyboard input, and then returns the value from the keyboard. If the user inputs an expression, the function evaluates it and returns its value. This function is useful for implementing menu-driven applications.

input can also return user input as a string, rather than a numeric value. To obtain string input, append 's' to the function's argument list.

• name = input('Enter address: ','s');
  

Pausing During Execution

Some M-files benefit from pauses between execution steps. For example, the petals.m script, shown in the "Simple Script Example" section, pauses between the plots it creates, allowing the user to display a plot for as long as desired and then press a key to move to the next plot.

The pause command, with no arguments, stops execution until the user presses a key. To pause for n seconds, use

• pause(n)
  

Calling Functions

Subscripting and Indexing