File Processing (5 December 2018)

What is Stream?
A sequence of character including Input, Output and even file.

There are 3 standard streams activated when a C program running :

1. Standard Input Stream : Keyboard
2. Standard Output Stream : Monitor
3. Standard Error Stream : Error Message

What is File?

File is a collection of record which is a collection of field of block of byte that is a collection of bit.

• Text file can be saved as a text format or ascii file
• Binary file storing numerical data in affixed format

What is Buffer?

A part of the memory used as a temporary storage before a data moved to a file that also can be called as stream pointer.

How to use buffer : FILE *fp;

fp is a file pointer pointing to the start of the buffer area.

How to open a file?

Inside <stdio.h> there is fopen() that can be used to open a file.

Can write it as FILE *fopen (const char *filename, const char *mode);

List of mode value:

• "r" : open and read file
• "w"  : create and write a file
• "a" :  open a file for data append
• "r+" : open and read or write the file
• "w+" : create and read or write a file
• "a+" : open and read or append a file
• "rb" : open and read a binary file
• "wb" : open and write a binary file

How to close a file?

Inside <stdio.h>  there is fclose() that can be used to close a file.

Can write it as int fclose (FILE *stream);

It will return 0 if successful, and EOF if error which equals to -1

Also can use fcloseall() inside <stdio.h> to close all active stream except stdin, stdout, stdprn, stderr, and stdaux.

Can write it as int fcloseall(void);

It will return the number of stream closed if successful, and return EOF instead.

How to input and output a file?

• fgetc(INPUT)
• fputc(OUTPUT)
• fgets(INPUT)
• fputs(OUTPUT)
• fscanf(INPUT)
• fprintf(OUTPUT)
• fwrite
• fread
• feof