# 5.5: Functions With Multiple Input Variables

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Functions can take more than one input variable. For example, the following function in Listing 5.2 takes two input variables, a and b:

Listing 5.2: A function that computes the sum of squares of two numbers

function res = sum_squares(a, b)
res = a^2 + b^2;
end

This function computes the sum of squares of two numbers, a and b.

If we call it from the Command Window with arguments 3 and 4, we can confirm that the sum of their squares is 25.

>> ss = sum_squares(3, 4)
ss = 25

The arguments you provide are assigned to the input variables in order, so in this case 3 is assigned to a and 4 is assigned to b. MATLAB checks that you provide the right number of arguments; if you provide too few, you get

>> ss = sum_squares(3)
Not enough input arguments.

Error in sum_squares (line 4)
res = a^2 + b^2;

This error message might be confusing, because it suggests that the problem is in sum_squares rather than in the function call. Keep that in mind when you’re debugging.

If you provide too many arguments, you get

ss = sum_squares(3, 4, 5)
Error using sum_squares
Too many input arguments.

That’s a better error message, because it’s clear that the problem isn’t in the function, it’s in the way we’re using the function.

This page titled 5.5: Functions With Multiple Input Variables is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Allen B. Downey (Green Tea Press) via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.