C Tutorial/stdio.h/freopen
freopen
Item Value Header file stdio.h Declaration FILE *freopen(const char *fname, const char *mode, FILE *stream); Function associates an existing stream with a different file. Return returns a pointer to stream on success or a null pointer on failure.
Legal Values for the mode Parameter
Mode Meaning "r" Open text file for reading "w" Create a text file for writing "a" Append to text file "rb" Open binary file for reading "wb" Create binary file for writing "ab" Append to a binary file "r+" Open text file for read/write "w+" Create text file for read/write "a+" Open text file for read/write "rb+" or "r+b" Open binary file for read/write "wb+" or "w+b" Create binary file for read/write "ab+" or "a+b" Open binary file for read/write