iswblank() function in C++ STL

The iswblank () function in C++ is used to check if the given wide character is blank not. It is present in “ctype.h” header file in C language and “cctype” header file in C++ Standard template library (STL).

Syntax of iswblank is as follows

int iswblank(wint_t ch)

Return Type − returns non zero value if it contains blank spaces and value 0 if it doesn’t.

Parameters − ch − This is the character to be checked.


Input − string str = “I Love Myself”

Output − total number of spaces is − 2

Input − string str = “Myself”

Output − total number of spaces is − 0

Approach used in the below program is as follows −

  • Input the string to check whether it contains spaces or not.

  • Call the function iswblank() and pass the given string to the function as a parameter for the final result.

  • Catch the non-zero integer value in a variable to print the final result.


 Live Demo

#include <ctype.h>
#include <iostream>
using namespace std;
int main(){
   setlocale(LC_ALL, "en_US.UTF-8");
   wchar_t str[] = L"\u0757\u077c\u0020\u00c5\u00d5\u00dd\u0009\u00a5";
   int count = 0;
   for (int i=0; i<wcslen(str); i++) {
      if (iswblank(str[i]))
         count ++;
   cout << L"Number of blank characters in \"" << str << "\" = " << count;
   return 0;


IF we run the above code it will generate the following output −

Number of blank characters in "ݼݗ ÅÕÝ¥" = 2

Updated on: 27-Feb-2020


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