The book you are reading is crap. Avoid the book and tell others to do the same.
<conio.h>is a system-specific header and not guaranteed to be available on many platforms.- The result of
fgetcmust never be stored in acharvariable. - The function
feofmust never be used in a loop condition.
The book probably comes from the 1980s or early 1990s. There is a function delay in Turbo Pascal that takes milliseconds. Maybe that’s the one the author means.
solved What is delay() in C? Is it a system function?