File pointers in C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a file pointer in C?

A file pointer in C is a variable of type FILE * that stores the address of a file stream. It is used to access and manipulate files.

beginner

How do you open a file using a file pointer?

You use the fopen() function, which returns a FILE *. For example: FILE *fp = fopen("file.txt", "r"); opens a file for reading.

beginner

What does fclose() do?

fclose() closes the file associated with the file pointer and frees resources. Always close files to avoid memory leaks.

beginner

How can you check if a file was opened successfully?

Check if the file pointer is NULL. If fopen() returns NULL, the file did not open successfully.

intermediate

What is the role of fseek() with file pointers?

fseek() moves the file pointer to a specific location in the file, allowing you to read or write at that position.

What type is a file pointer in C?

A void *

B int

C char *

D FILE *

File pointers are of type FILE * in C.

Which function opens a file and returns a file pointer?

A fclose()

B fprintf()

C fopen()

D fread()

fopen() opens a file and returns a FILE *.

What does fclose() do?

A Closes a file

B Reads from a file

C Writes to a file

D Moves the file pointer

fclose() closes the file and releases resources.

How do you check if a file failed to open?

A Check if file pointer is 0

B Check if file pointer is NULL

C Check if file pointer is -1

D Check if file pointer is 1

If fopen() returns NULL, the file did not open.

Which function moves the file pointer to a new position?

A fseek()

B fwrite()

C fread()

D ftell()

fseek() moves the file pointer to a specified location.

Explain what a file pointer is and how it is used in C programming.

Think about how you open and work with files in C.

Describe the steps to safely open, use, and close a file using file pointers.

Remember the order of operations when working with files.