Unformatted Input/Output Functions with Example: C Language

In our earlier post i have discussed about sequential and compound statements. Now in this post we will discuss about unformatted i/o functions. There are several standard library functions available in this category - those that can deal with a single character and those that can deal with a string of characters. The various unformatted input/output functions in C are shown below:

getchar( ) and putchar( )

Even though getchar( ) and putchar( ) looks like functions, they are not. They are the macros that are used to read and display a character. The syntax to read a character shown below:

“ch = getchar( )” will reads a character from the keyboard and copy it into memory area which is identified by the variable ch. No arguments are required for this macro. Once the character is entered from the keyboard, the user has to press Enter key.

“putchar(ch)” outputs a character stored in a variable on the monitor. The variable should be passed as parameter as shown in the above syntax.

Example1
main()
{
 char ch;
 clrscr();
 ch = getchar();
 putchar(ch);
 getch();
}

getch(), getche() and putch()

The functions getch() and getche() are used to read a character from the keyboard, similar to getchar(). Both functions don’t need a return key pressed to terminate the reading of a character. A character entered will itself terminates reading. 

In case of getch(), the character entered is not displayed or echoed on the screen, whereas in getche(), the character entered is echoed or displayed on the screen. Syntax for both the macros

ch = getch();            /*Typed character will not be displayed on the screen*/
ch = getche();            /*Typed character will be displayed on the screen*/

Now, we have to display the inputted character on the screen, putch() macro is introduced.
“putch(ch)” This function outputs a character stored in the memory, on the monitor. The variable should be passed as parameter to the functions. In the above syntax ‘ch’ is used as an argument and its value is displayed on the screen.

Example2:
main()
{
  char ch;
  clrscr();
  ch = getche();
  putch(ch);
  getch();
}

gets() and puts()

These functions are used to read a set of characters (string) from the keyboard and display a set of characters (string) on the screen.

char str[5];
gets(str);        /* Reads a set of characters into memory area str */
puts(str);         /* Displays a set of characters from memory area str */

Example3
main()
{
  char str[10];
  clrscr();
  gets(str);
  puts(str);
  getch();
}

Formatted I/O Functions