function
<cctype>

isblank

int isblank ( int c );
Check if character is blank
Checks whether c is a blank character.

A blank character is a space character used to separate words within a line of text.

The standard "C" locale considers blank characters the tab character ('\t') and the space character (' ').

Other locales may consider blank a different selection of characters, but they must all also be space characters by isspace.

For a detailed chart on what the different ctype functions return for each character of the standard ASCII character set, see the reference for the <cctype> header.

In C++, a locale-specific template version of this function (isblank) exists in header <locale>.

Compatibility note: Standardized in C99 (C++11).

Parameters

c
Character to be checked, casted to an int, or EOF.

Return Value

A value different from zero (i.e., true) if indeed c is a blank character. Zero (i.e., false) otherwise.

Example

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
/* isblank example */
#include <stdio.h>
#include <ctype.h>
int main ()
{
  char c;
  int i=0;
  char str[]="Example sentence to test isblank\n";
  while (str[i])
  {
    c=str[i];
    if (isblank(c)) c='\n';
    putchar (c);
    i++;
  }
  return 0;
}


This code prints out the C string character by character, replacing any blank character by a newline character. Output:
Example
sentence
to
test
isblank

See also