Can I call a function from another function and not come back?

Hi @Gavin,

Your concerns about function management in MATLAB are valid, especially considering your experience with assembly language. Let me delve into the details of how MATLAB handles function calls, addressing your specific points about stack management and the necessity of additional functions. In MATLAB, when one function calls another, it indeed involves pushing the current execution context onto the call stack. However, MATLAB is designed to manage this process efficiently. Here’s a breakdown:

Stack Management: Unlike lower-level languages like assembly where stack overflow can be a significant concern due to manual control over the call stack, MATLAB abstracts these complexities. It automatically handles stack depth and memory allocation, allowing you to focus on your code's logic rather than low-level mechanics.

Recursion and Performance: While excessive recursion can lead to performance issues or stack overflow, this is typically a concern only when functions call themselves or each other in a deeply nested manner.

No Need for an Intermediary Function: Your initial thought about needing a third function may stem from a desire to simplify or control flow. However, as demonstrated in your examples, structuring functions hierarchically without an intermediary is perfectly acceptable and often preferable for clarity and maintainability.

Example Code Review

The example code snippets provided below illustrate how to structure function calls in MATLAB:

Main Function (mainFunction.m): This serves as the entry point, calling `secondaryFunction` and handling its output.

Secondary Function (secondaryFunction.m): It processes data and optionally calls another function (anotherFunction), demonstrating modularity.

Another Function (`anotherFunction.m): This further processes the data received from secondaryFunction.

So, you can see this hierarchical approach allows for clear data flow and logical separation of tasks.

Function Definitions

Main Function (mainFunction.m)

This is the entry point where you call your secondary function.

   function mainFunction()
       % Sample data to pass to the secondary function
       inputData = 10;

       % Call the secondary function
       result = secondaryFunction(inputData);

       % Display result
       fprintf('Result from secondaryFunction: %d\n', result);
   end

Secondary Function (secondaryFunction.m)

This function performs a calculation and may call another function if needed.

   function output = secondaryFunction(data)
       % Perform some operation on the input data
       processedData = data * 2;  % Example operation

       % Optionally call another function
       output = anotherFunction(processedData);
   end

Another Function (anotherFunction.m)

This function takes processed data from the secondary function.

   function output = anotherFunction(value)
       % Further processing of value
       output = value + 5;  % Example operation
   end

Step-by-Step Instructions to Test

Create the Functions

• Open MATLAB and create three separate .m files named mainFunction.m, secondaryFunction.m, and anotherFunction.m.

Copy and Paste Code

• Copy the respective code snippets provided above into each file.

Run the Main Function

• In the MATLAB Command Window, type mainFunction() and press Enter.

Observe Output

You should see an output similar to:

     Result from secondaryFunction: 25

This indicates that the flow through the functions is working correctly.

Please see attached.

If you still have any further questions, please let us know.