C I/O

File I/O

For C File I/O you need to use a FILE pointer, which will let the program keep track of the file being accessed. To open a file you need to use the fopen function, which returns a FILE pointer.

FILE *fopen(const char *filename, const char *mode);

The modes are:

r	open for reading
w	open for writing (file need not exist)
a	open for appending (file need not exist)
r+	open for reading and writing, start at beginning
w+	open for reading and writing (overwrite file)
a+	open for reading and writing (append if file exists)