Please explain thoroughly

20. Complete the function that extract the extension from a file name. file name points to a string containing a file name. The function should store the extension on the file name in the string pointed to by extension. For example, if the file name is "memo.txt', the function will store "txt in the string pointed to by extension. If the file name doesn't have an extension, the function should store an empty string (a single null character) in the string pointed to by extension. You can use string library functions such as strycpy void get extension (char kfile namer char *extension)