Figure $1$: Small circle starts in the middle $($left$)$; triples in size when $3$ is pressed $($middle$)$ and then moves and resets to original size when mouse is clicked, then doubles in size when $2$ is pressed.

Here$$s a description of how to go about your work Step $1$

Define a function called calculate$\_$size$().$ This function should have two input parameters: the old diam$-$ eter of the circle $($an integer$),$ and the digit key that was pressed on the keyboard $($a string$).$ The function should first convert the digit from a string to an integer $($hint: use the int$()$ function to do this$)$ and then multiply it with the old diameter and return the result. This isn$$t a lot of work for the function to do $($in fact, it might just be $1$ line of code$),$ but the point is to practice using parameters and return values. Importantly, the function should not use global variables in any way.

Step $2$

Once you are sure your function from step $1$ is working, you can add the interactive parts of your program. Make sure to use a good Model$-$View$-$Controller design and decide what your global variables will be$,$ then add your setup$(),$ draw$(),$ mouseClicked$()$ and keyPressed$()$ functions. Call your calculate$\_$size$()$ func$-$ tion in the right place when you need to change the size of the circle $($hint: this will only be in keyPressed$()).$