What happens when code is run with input$()$ vs input $($x$)?$

input$()$ and input $(x)$ do exactly the same thing; using an argument is optional.

input$()$ will not store anything that was input, while will store what was typed into the variable $x.$

will collect input without any prompt to the user while will print out whatever value is stored in the variable $x$ prior to collecting the input.

input$()$ will wait for the user to type something, while will print the letter $x$ prior to collecting the input.