C++ || How To Check If A String Is Empty Or Only Contains Whitespace Using C++

December 05, 2020 admin No comments

The following is a module with functions which demonstrates how to determine whether a string is empty, or consists only of white-space characters using C++.

1. Is Null Or Whitespace

The example below demonstrates the use of ‘Utils::isNullOrWhitespace‘ to determine whether a string is empty, or consists only of white-space characters.





		
		
			1. Is Null Or Whitespace
			
C++
			
			// Is Null Or Whitespace

// Declare values
std::string words[] = { "Kenneth", "", "Jennifer", " ", "Lynn", "\n\t", "Sole" };

// Check to see which is empty
for (auto& word: words) {
    bool isEmpty = Utils::isNullOrWhitespace(word);
    std::cout << "Word: " << word << ", Is Empty: " << (isEmpty ? "True" : "False") << std::endl;
}

// expected output:
/*
    Word: Kenneth, Is Empty: False
    Word: , Is Empty: True
    Word: Jennifer, Is Empty: False
    Word:  , Is Empty: True
    Word: Lynn, Is Empty: False
    Word:
            , Is Empty: True
    Word: Sole, Is Empty: False
*/
			
				
					
				
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						// Is Null Or Whitespace
 
// Declare values
std::string words[] = { "Kenneth", "", "Jennifer", " ", "Lynn", "\n\t", "Sole" };
 
// Check to see which is empty
for (auto& word: words) {
    bool isEmpty = Utils::isNullOrWhitespace(word);
    std::cout << "Word: " << word << ", Is Empty: " << (isEmpty ? "True" : "False") << std::endl;
}
 
// expected output:
/*
    Word: Kenneth, Is Empty: False
    Word: , Is Empty: True
    Word: Jennifer, Is Empty: False
    Word:  , Is Empty: True
    Word: Lynn, Is Empty: False
    Word:
            , Is Empty: True
    Word: Sole, Is Empty: False
*/

2. Utils Namespace

The following is the Utils Namespace. Include this in your project to start using!





		
		
			Utils Namespace
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Dec 5, 2020
//    Taken From: http://programmingnotes.org/
//    File:  Utils.h
//    Description: Handles general utility functions
// ============================================================================
#pragma once
#include <string>
#include <cctype>
#include <algorithm>

namespace Utils {
    /**
    * FUNCTION: isNullOrWhitespace 
    * USE: Indicates whether a specified string is empty, or consists only 
    *    of whitespace characters
    * @param str: The source string
    * @return: True if str is Empty, or consists of only whitespace characters, 
    *    False otherwise
    */
    bool isNullOrWhitespace(const std::string& str) {
        return str.empty()
            || std::all_of(str.begin(), str.end(), [](char c) {
            return std::isspace(static_cast<unsigned char>(c));
        });
    }
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Dec 5, 2020
//    Taken From: http://programmingnotes.org/
//    File:  Utils.h
//    Description: Handles general utility functions
// ============================================================================
#pragma once
#include <string>
#include <cctype>
#include <algorithm>
 
namespace Utils {
    /**
    * FUNCTION: isNullOrWhitespace 
    * USE: Indicates whether a specified string is empty, or consists only 
    *    of whitespace characters
    * @param str: The source string
    * @return: True if str is Empty, or consists of only whitespace characters, 
    *    False otherwise
    */
    bool isNullOrWhitespace(const std::string& str) {
        return str.empty()
            || std::all_of(str.begin(), str.end(), [](char c) {
            return std::isspace(static_cast<unsigned char>(c));
        });
    }
}// http://programmingnotes.org/

3. More Examples

Below are more examples demonstrating the use of the ‘Utils‘ Namespace. Don’t forget to include the module when running the examples!





		
		
			More Examples
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Dec 5, 2020
//    Taken From: http://programmingnotes.org/
//    File:  program.cpp
//    Description: The following demonstrates the use of the Utils Namespace
// ============================================================================
#include <iostream>
#include <string>
#include <exception>
#include "Utils.h"

void display(const std::string& message);

int main() {
    try {
        // Declare values
        std::string words[] = { "Kenneth", "", "Jennifer", " ", "Lynn", "\n\t", "Sole" };

        // Check to see which is empty
        for (auto& word: words) {
            bool isEmpty = Utils::isNullOrWhitespace(word);
            display("Word: " + word + ", Is Empty: " + (isEmpty ? "True" : "False"));
        }
    } catch (std::exception& e) {
        display("\nAn error occurred: " + std::string(e.what()));
    }

    std::cin.get();
    return 0;
}

void display(const std::string& message) {
    std::cout << message << std::endl;
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Dec 5, 2020
//    Taken From: http://programmingnotes.org/
//    File:  program.cpp
//    Description: The following demonstrates the use of the Utils Namespace
// ============================================================================
#include <iostream>
#include <string>
#include <exception>
#include "Utils.h"
 
void display(const std::string& message);
 
int main() {
    try {
        // Declare values
        std::string words[] = { "Kenneth", "", "Jennifer", " ", "Lynn", "\n\t", "Sole" };
 
        // Check to see which is empty
        for (auto& word: words) {
            bool isEmpty = Utils::isNullOrWhitespace(word);
            display("Word: " + word + ", Is Empty: " + (isEmpty ? "True" : "False"));
        }
    } catch (std::exception& e) {
        display("\nAn error occurred: " + std::string(e.what()));
    }
 
    std::cin.get();
    return 0;
}
 
void display(const std::string& message) {
    std::cout << message << std::endl;
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

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Posted in: Basic, C++ Tags: c++

C++ || How To Check If A String Is Empty Or Only Contains Whitespace Using C++

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