Programming

Nested Functions

You can define one or more functions within another function in MATLAB. These inner functions are said to be nested within the function that contains them. You can also nest functions within other nested functions.

This section covers the following topics on using nested functions in MATLAB:

• Writing Nested Functions
• Calling Nested Functions
• Variable Scope in Nested Functions
• Using Function Handles with Nested Functions
• Examples of Nested Functions

Writing Nested Functions

To write a nested function, simply define one function within the body of another function in an M-file. Like any M-file function, a nested function contains any or all of the components described in Basic Parts of an M-File. In addition, you must always terminate a nested function with an end statement:

• function x = A(p1, p2)
  ...
     function y = B(p3)
     ...
     end
  ...
  end
  

Note    M-file functions don't normally require a terminating end statement. This rule does not hold, however, when you nest functions. If an M-file contains one or more nested functions, you must terminate all functions (including subfunctions) in the M-file with end, whether or not they contain nested functions.

Example -- More Than One Nested Function

This example shows function A and two additional functions nested inside A at the same level:

• function x = A(p1, p2)
  ...
     function y = B(p3)
     ...
     end
  
     function z = C(p4)
     ...
     end
  ...
  end
  

Example -- Multiply Nested Functions

This example shows multiply nested functions, C nested inside B, and B in A:

• function x = A(p1, p2)
  ...
     function y = B(p3)
     ...
        function z = C(p4)
        ...
        end
     ...
     end
  ...
  end
  

Primary M-File Functions

Calling Nested Functions

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