MATLAB: How to convert a script to a function

scripts functions

I am trying to convert the attached script into a function to produce the same figure and results for a plot of the (for argument's sake) Earth orbiting the Sun. I have attached what I have of the function so far, but I am struggling to understand what I have done wrong and how to proceed. The function has pseudocode explanations of variables etc. Any help would be much appreciated. Regards, AR

Best Answer

There may be other things wrong, but these 2 lines are surely not what you want. You pass in p and v as input arguments, then you just set them to empty here:
p = []; % Celestial body initial positions vector 
        % Will be N by 2 e.g. p1 = [px,py]
v = []; % Celestial body initial velocities vector
        % Also N by 2 e.g. v1 = [vx,vy]
It's not obvious what all the lines of code above this are all about either - they seem somewhat pointless.
You need to use the input arguments that you pass in - e.g. mass, not m as you do further down the code (or you could change your input argument name to 'm', but I much prefer 'mass' as it says what it is, 'm' is meaningless).
The biggest difference between a function and script is the arguments that you pass into it instead of creating within the function. Never over-write the input arguments!
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