The document discusses various unformatted console I/O functions in C like printf, getchar, putchar, fgetchar, getch, and getche. It explains that getch doesn't wait for enter while getche echoes the character. It also covers low-level disk I/O functions like fgetc and fputc that read and write characters individually from files. The document provides examples of opening a file, reading contents character by character using getc, and copying the contents of one file to another.

1. Unformatted Console I/O Functions
main( )
{
printf ( ”Delete all files Y/N” ) ;
ch = getchar( ) ;
/* or ch = fgetchar( ) ; */
putch ( ch ) ;
putchar ( ch ) ;
fputchar ( ch ) ;
}
printf ( ”Press any key” ) ;
getch( ) ;
printf ( ”Another disk Y/N” ) ;
ch = getche( ) ;
same
char ch ;

2. Peculiarities
getch( ) - Doesn’t wait for enter.
getche( ) - Echoes character.
getchar( ) - Waits for enter. Macro.
fgetchar( ) - Waits for enter. Function.

3. Disk I/O
High Level / Std Disk I/O Low Level
Text Binary
Formatted Unformatted
char
int
fprintf( )
float
fscanf( )
string
char - getc ( ), fgetc( )
putc ( ), fputc( )
Reads / Writes
char by char
int -
float - No Std. Library Function
string - fgets( ), fputs( )
Reads / Writes
line by line
file

4. Bufferred I/O
Memory
))
Buffer
CCHH11PPRR11..CC
Disk

5. Displaying File Contents
# include ”stdio.h”
char fname[13] ;
printf ( ”Enter file name” ) ;
gets ( fname ) ;
fopen ( ) ;
main( )
{
char ch ;
FILE *fp ;
fp = fname, ”r”
while ( 1 )
{
ch = getc ( ) ;
if ( ch == EOF )
break ;
printf ( ”%c”, ch ) ;
}
fclose ( ) ;
}
fp
fp

6. typedef
unsigned long int i, j ; typedef unsigned long int uli ;
struct employee
{ ___
} ;
struct employee e1, e2 ;
struct a
{ __
char *p ;
} ;
typedef struct a FILE ;
uli i, j ;
struct employee
{ ___
} ;
typedef struct employee emp ;
emp e1, e2 ;
FILE *fp ;

7. # include ”stdio.h”
char fname[13] ;
printf ( ”Enter file name” ) ;
gets ( fname ) ;
fopen ( ) ;
main( )
{
char ch ;
FILE *fp ;
fp = fname, ”r”
while ( 1 )
{
ch = getc ( ) ;
if ( ch == EOF )
break ;
printf ( ”%c”, ch ) ;
}
fclose ( ) ;
}
fp
fp
A Fresh Look
Buffer
40
fp p
40
ffpp -->> pp == ffpp -->> pp ++ 11 ;;

8. Tips
fopen( ) - Standard Library Function to open the file.
fopen ( fname, ”r” ) ; - Returns NULL if file not found.
Every file ends with a char with ascii value 26.
EOF is a macro.
# define EOF -1
FILE is a structure defined in stdio.h
getc( ) reads char also shifts pointer to next char.

9. Copying Files
char fname[13] , target[13] ;
printf ( ”Enter source target file names” ) ;
gets ( fname ) ;
gets ( target ) ;
ft = fopen ( target, ”w” ) ;
# include ”stdio.h”
fopen ( ) ;
main( )
{
char ch ;
FILE *fs, *ft ;
fs = fname, ”r”
while ( 1 )
{
ch = getc ( ) ;
if ( ch == EOF )
break ;
putc ( ) ;
ch, ft
}
fclose ( ) ;
fs
fs fclose ( ft ) ;
}

10. Copying Files
char fname[13] , target[13] ;
printf ( ”Enter source target file names” ) ;
gets ( fname ) ;
gets ( target ) ;
ft = fopen ( target, ”w” ) ;
# include ”stdio.h”
fopen ( ) ;
main( )
{
char ch ;
FILE *fs, *ft ;
fs = fname, ”r”
while ( 1 )
{
ch = getc ( ) ;
if ( ch == EOF )
break ;
putc ( ) ;
ch, ft
}
fclose ( ) ;
fs
fs fclose ( ft ) ;
}