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Call a function: Difference between revisions
→{{header|Matlab/Octave}}: call a function
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No formal distinction between subroutines and functions.
Arguments can be passed by value or by reference.</lang>
=={{header|MATLAB}} / {{header|Octave}}==
<lang Matlab>
% Calling a function that requires no arguments
function a=foo();
a=4;
end;
x = foo();
% Calling a function with a fixed number of arguments
function foo(a,b,c);
%% function definition;
end;
foo(x,y,z);
% Calling a function with optional arguments
function foo(a,b,c);
if nargin<2, b=0; end;
if nargin<3, c=0; end;
%% function definition;
end;
foo(x,y);
% Calling a function with a variable number of arguments
function foo(varargin);
for k=1:length(varargin)
arg{k} = varargin{k};
end;
foo(x,y);
% Calling a function with named arguments
%% does not apply
% Using a function in statement context
%% does not apply
% Using a function in first-class context within an expression
% Obtaining the return value of a function
function [a,b]=foo();
a=4;
b='result string';
end;
[x,y] = foo();
% Distinguishing built-in functions and user-defined functions
fun = 'foo';
if (exist(fun,'builtin'))
printf('function %s is a builtin\n');
elseif (exist(fun,'file'))
printf('function %s is user-defined\n');
elseif (exist(fun,'var'))
printf('function %s is a variable\n');
else
printf('%s is not a function or variable.\n');
end
% Distinguishing subroutines and functions
% there are only scripts and functions, any function declaration starts with the keyword function, otherwise it is a script that runs in the workspace
% Stating whether arguments are passed by value or by reference
% arguments are passed by value, however Matlab has delayed evaluation, such that a copy of large data structures are done only when an element is written to.
</lang>
=={{header|PARI/GP}}==
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