Using output variables from one function as inputs for another

I'm trying to use the 'days' and 'daily_deaths' outputs from my 'process_data' function as inputs for my 'global_deaths' function, but I have no idea how to set it up. I've searched this forum for people asking similar questions, but the answers they recieved only further confused me. Can anybody help me?

function global_deaths(daily_deaths, days, avg_days)
process_data();
plot(days,daily_deaths);
grid on
txt = sprintf('Daily deaths from day %d to day %d of the pandemic',min(days(:)),max(days(:)));
title(txt)
ylabel('Deaths');
xlabel('Day')
axis([min(days(:)) max(days(:)) min(daily_deaths(:)) max(daily_deaths(:))]);
hold on
avg_days = movmean(daily_deaths,[6 0])
hold off
end

Answer 1

[DGM]

Not knowing what processdata() does or whether it has any outputs at all, I can't say.

When you define a function, define its input arguments and output arguments. If you don't have any output arguments, then you don't have anything to pass to another function (unless you're abusing globals or using nested functions with shared variables).

This is a basic example of two functions:

% take the output from one function
intermediateresult = addnumbers(3,4)
% and pass it to another
finalresult = multiplynumbers(intermediateresult,3)


% function is defined with input arguments and output arguments
function out = addnumbers(A,B)
	out = A+B;
end

% again, function has input and output arguments
function out = multiplynumbers(A,B)
	out = A.*B;
end

The result is (3+4)*3=21

The two functions are independent scopes. A,B in the first function are not the same conceptual entities as the A and B in the second function. They exist only in their respective scope.

Answer 2

[Jan]

If the variables "days" and "daily_deaths" are output of the function process_data(), you have to catch the outputs:

[days, daily_deaths] = process_data();
plot(days,daily_deaths);