A positive integer $x$ expressed in decimal $($base $10)$ can be expressed using binary $($base $2)$ by repeatedly dividing $x$ by $2$ and determining the remainder. The binary value is then constructed using the remainders written in reverse order. For example, to express $19$ as a binary number

$192=9$ remainder $1$

$92=4$ remainder $1$

$42=2$ remainder $0$

$22=1$ remainder $0$

$12=0$ remainder $1$

So $19$ expressed as a binary number is $10011.$

Write a function called binary $(x)$ that takes in the input argument of a positive integer $x$ and returns a string of the value of $x$ expressed as a binary number using MATLAB.