Which of the following cannot be used with ungetc()?

In C, which library is used for file operations such as reading and writing files?

A. stdio.h

B. iostream.h

C. fileio.h

D. files.h

Which function is used to open a file in C for writing?

A. fopen()

B. open()

C. writefile()

D. createfile()

What does 'FILE' represent in C when working with files?

A. A built-in data type for files

B. A file descriptor

C. A file pointer

D. A file structure

How do you check if a file was opened successfully in C?

A. Use the 'filestatus' variable

B. Check the return value of fopen()

C. Use the 'fileopen' function

D. Check the file's size