How do I put variable values into a text string in MATLAB?

Question

I'm trying to write a simple function that takes two inputs, x and y, and passes these to three other simple functions that add, multiply, and divide them. The main function should then display the results as a string containing x, y, and the totals.

I think there's something I'm not understanding about output arguments. Anyway, here's my (pitiful) code:

function a=addxy(x,y)
a=x+y;

function b=mxy(x,y)
b=x*y;

function c=dxy(x,y)
c=x/y;

The main function is:

function [d e f]=answer(x,y)
d=addxy(x,y);
e=mxy(x,y);
f=dxy(x,y);
z=[d e f]

How do I get the values for x, y, d, e, and f into a string? I tried different matrices and stuff like:

['the sum of' x 'and' y 'is' d]

but none of the variables are showing up.

Two additional issues:

• Why is the function returning "ans 3" even though I didn't ask for the length of z?
• If anyone could recommend a good book for beginners to MATLAB scripting I'd really appreciate it.

Answer 1

I just realized why I was having so much trouble - in MATLAB you can't store strings of different lengths as an array using square brackets. Using square brackets concatenates strings of varying lengths into a single character array.

    >> a=['matlab','is','fun']

a =

matlabisfun

>> size(a)

ans =

     1    11

In a character array, each character in a string counts as one element, which explains why the size of a is 1X11.

To store strings of varying lengths as elements of an array, you need to use curly braces to save as a cell array. In cell arrays, each string is treated as a separate element, regardless of length.

>> a={'matlab','is','fun'}

a = 

    'matlab'    'is'    'fun'

>> size(a)

ans =

     1     3

Answer 2

Here's how you convert numbers to strings, and join strings to other things (it's weird):

>> ['the number is ' num2str(15) '.']
ans =
the number is 15.