C Library Function isprint( )

In this tutorial, you will learn about C library function isprint() which is a character handling function used to check whether its argument can be displayed on the screen (including the space character) or not.

As discussed earlier, we have to include ctype.h header file for using isprint( ) standard character library function.

#include <ctype.h>

C Library Function isprint( ): Function prototype

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int isprint( int ch);

This function checks whether its argument can be displayed on the screen (including the space character) or not.

It returns a true value if its argument is a printing character including a space and zero (0) otherwise.

Demonstration of C isprint( )

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

int main()
{
   printf("Demonstration of isprint():\n");
   printf("\n%s%s", isprint('$') ? "$ is a " : "$ is not a ", "printing character");
   printf("\n%s%s%s", "Space", isprint(' ') ? " is a " : " is not a ", "printing character");
   printf("\n%s%s%s", "Newline", isprint('\n') ? " is a " : " is not a ", "printing character");

   return 0;
}

Output

Demonstration of isprint():

$ is a printing character
Space is a printing character
Newline is not a printing character

Explanation
In the above example, standard character library function isprint determines whether its argument is a printing character or not.

Conditional operator ?: does the selection between two strings "is a" and "is not a".

Note: isprint function recognize space as a printing character.

This can be simply done with the help of if...else statements.

Example of C library function isprint() using if … else statement.

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


int main()
{
   printf("Demonstration of isprint( ):\n");

   if( isprint('$') == 0)
     printf("\n$ is not printing character");
   else
     printf("\n$ is a printing character");

   if( isprint(' ') == 0)
     printf("\nspace is not printing character");
   else
     printf("\nspace is a printing character");

   if( isprint('\n') == 0)
     printf("\nNewline is not printing character");
   else
     printf("\nNewline is a printing character");

   return 0;
}

Output

Demonstration of isprint():

$ is a printing character
Space is a printing character
Newline is not a printing character

Explanation
In this example, we have used if...else statements instead of a conditional operator.
Here, if...else statement does the selection between two strings.