Using only basic POSIX I$/$O$,$ write a program that opens a file given on the command and displays its contents $($assumed to be ASCII text$)$ to stdout, but whenever a digit would be displayed, the program instead shows an X$.$ So a file containing "I was born on the $4$th of July, $1976"$ would display "I was born on the Xth of July, XXXX$".$ Use a buffer size of $16$ bytes when reading from the file.