Skip to content
Related Articles

Related Articles

Improve Article

isblank() in C/C++

  • Difficulty Level : Medium
  • Last Updated : 26 Apr, 2018
Geek Week

The isblank()function returns non-zero if ch is a character for which isspace() returns true and is used to separate words. Thus for English, the blank characters are space and horizontal tab.

Header File : 
ctype.h

Declaration : 
int isblank(int ch)

difference between isblank() and isspace()
The isspace() simply return true if the character is a space. In other words blank character is a space character used to separate words within a line of text and isblank() is used to identify it.

isblank() considers blank characters the tab character (‘\t’) and the space character (‘ ‘).
isspace() considers space characters : (‘ ‘) – Space, (‘\t’) – Horizontal tab, (‘\n’) – Newline, (‘\v’) – Vertical tab, (‘\f’) – Feed, (‘\r’) – Carriage return

Examples:

Input:  Geeks for Geeks
Output: Geeks
        for 
        Geeks

Explanation: Since there are 2 spaces for Geeks for Geeks marked by an underscore( _ ) :
Geeks_for_Geeks
we replace the space with a newline character.



isblank() C++ Program:
This code prints out the string character by character, replacing any blank character by a newline.




// CPP program to demonstrate working
// of isblank()
#include <ctype.h>
#include <iostream>
using namespace std;
  
int main()
{
    string str = "Geeks for Geeks";
    int i = 0;
  
    // to store count of blanks
    int count = 0;
    while (str[i]) {
  
        // to get ith character
        // from string
        char ch = str[i++];
  
        // mark a new line when space
        // or horizontal tab is found
        if (isblank(ch)) {
            cout << endl;
            count++;
        }
        else
            cout << ch;
    }
  
       cout << "\nTotal blanks are : "
            << count << endl;
    return 0;
}

Output:

Geeks
for
Geeks
Total blanks are : 2
Want to learn from the best curated videos and practice problems, check out the C++ Foundation Course for Basic to Advanced C++ and C++ STL Course for foundation plus STL.  To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.



My Personal Notes arrow_drop_up
Recommended Articles
Page :