C isprint()

Those characters that occupies printing space are known as printable characters.

Printable characters are just the opposite of control characters which can be checked using iscntrl().

C isprint() Prototype

int isprint( int arg );

Function isprint() takes a single argument in the form of an integer and returns a value of type int.

Even though, isprint() takes integer as an argument, character is passed to the function. Internally, the character is converted to its ASCII value for the check.

If a character passed to isprint() is a printable character, it returns non-zero integer, if not it returns 0.

It is defined in <ctype.h> header file.

Example: C isprint() function

#include <ctype.h>
#include <stdio.h>

int main()
{
    char c;

    c = 'Q';
    printf("Result when a printable character %c is passed to isprint(): %d", c, isprint(c));

    c = '\n';
    printf("\nResult when a control character %c is passed to isprint(): %d", c, isprint(c));

    return 0;
}

Output

Result when a printable character Q is passed to isprint(): 16384
Result when a control character 
 is passed to isprint(): 0

Example: C Program to List all Printable Characters Using isprint() function.

#include <ctype.h>
#include <stdio.h>
int main()
{
   int c;
   for(c = 1; c <= 127; ++c)
   	if (isprint(c)!= 0)
             printf("%c ", c);
   return 0;
}

Output:

The printable characters are: 
  ! " # $ % & ' ( ) * + , - . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ? @ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ \ ] ^ _ ` a b c d e f g h i j k l m n o p q r s t u v w x y z { | } ~