"Parameter" vs "Argument"

Question

I got parameter and argument kind of mixed up and did not really pay attention to when to use one and when to use the other.

Can you please tell me?

Solution

A parameter is the variable which is part of the method’s signature (method declaration). An argument is an expression used when calling the method.

Consider the following code:

void Foo(int i, float f)
{
    // Do things
}

void Bar()
{
    int anInt = 1;
    Foo(anInt, 2.0);
}

Here i and f are the parameters, and anInt and 2.0 are the arguments.

Comments

[vol7ron]

Old post, but another way of saying it: argument is the value/variable/reference being passed in, parameter is the receiving variable used w/in the function/block.

[kasperhj]

Or, a method has parameters and takes arguments.

[Eduardo La Hoz Miranda]

Someday I will explode and it will be a shower of developer's lingo.

[ngDeveloper]

Why is it that within JavaScript, when you want to access the parameters of a function/method, you have to access the "arguments" variable? Shouldn't that be "parameters" instead?

[Caltor]

I remember it by saying "for the sake of argument, if we pass in anInt and 2.0". idioms.thefreedictionary.com/for+the+sake+of+argument

[B T]

@ngDeveloper Nope, it should be arguments. You get access to the list of argument values passed to the function. Consequently you don't get a list of the parameter names of the function, javascript doesn't give you a way to get that info.

[jimbo]

@BT You're correct that it should be arguments, but JS does give you a way to get the parameters. When you cast a function as a string, the names of parameters are in-tact if you parse them out. E.g. function foo(a, b) {} then (foo+'').split(/\W+/).slice(2,-1) produces ["a", "b"].

[B T]

@jimbojw I stand partially corrected ; ) Neat

[T.J. Crowder]

Citation for the above?

[LegendLength]

I feel like this is a case where the definitions should just be collapsed into 1. There's rarely a need to differentiate between the two concepts and if you really need to just label them 'internal' or 'external' parameters or something similar.

[Phil]

If you like analogies- Method is like salad bowl. Argument is like greens. Parameter is like salad.

[Emil]

For a non-technical perspective, the general definition of parameter (beyond programming), according to Cambridge Dictionary is a set of facts which describes and puts limits on how something should happen or be done. If you internalize this, then you'll remember that a method is bound/defined by parameters.

[provisota]

Brilliant! This question is torturing me for a long time! :) Thank you so much!

[rodrigo-silveira]

Yet another way to think of this: when you have code with hard-coded values, you can make it more generic by "parameterizing" it. That is, make it into a function with "parameters" that represent any arbitrary input.

[Quetzalcoatl]

Somtimes google doc string suggestions [google.github.io/styleguide/pyguide.html] has "Args" as what we formally define as "parameters" -- is it common to use "Params" instead of "Args" to document the arguments that a method receives?

[Kamafeather]

@Quetzalcoatl: I see they imported code from Copybara; in there args is often modelled as a iterable object; so it is not intended just in the usual meaning (aka: construct at programming-language level). Many methods in the project specify a Parameter called args, defined as an array of values (these are not defines as parameters, but they are just runtime values). So I think the docs author probably got confused. I would have used settings or options instead of args, to not confuse with the language-level arguments.

[ccpizza]

An easy way to remember: ARGV has been around since forever and has propagated from C/C++ to other languages like python, perl, ruby, js, etc, and stands for the array of values passed via the command line.