August 2021 – My Programming Notes

Monthly Archives: August 2021

C++ || How To Pad Left, Pad Right & Pad Center A String Of Fixed Length Using C++

August 02, 2021 admin No comments

The following is a module with functions which demonstrates how to pad left, pad right, and pad center a string of a fixed length using C++.

The functions demonstrated on this page left, right, and center aligns the characters in a string by padding them on the left and right with a specified character, of a specified total length.

The returned string is padded with as many padding characters needed to reach a length of the specified total width.

The padding character is user defined, but if no padding character is specified, the string is padded using a whitespace (‘ ‘).

1. Pad Left

The example below demonstrates the use of ‘Utils::padLeft‘ to right align the characters in a string by padding them on the left with a specified character, of a specified total length.

In this example, the default padding character is used to pad the string, which is a whitespace (‘ ‘).





		
		
			1. Pad Left
			
C++
			
			// Pad Left

// Declare string
std::string original = "<-Kenneth->";

// Get padding width
int width = 15;

// Display result
std::cout << "Original:   '" << original << "'" << std::endl;
std::cout << "Pad Left: '" << Utils::padLeft(original, width) << "'";

// expected output:
/*
    Original:   '<-Kenneth->'
    Pad Left:   '    <-Kenneth->'
*/
			
				
					
				
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						// Pad Left
 
// Declare string
std::string original = "<-Kenneth->";
 
// Get padding width
int width = 15;
 
// Display result
std::cout << "Original:   '" << original << "'" << std::endl;
std::cout << "Pad Left: '" << Utils::padLeft(original, width) << "'";
 
// expected output:
/*
    Original:   '<-Kenneth->'
    Pad Left:   '    <-Kenneth->'
*/

2. Pad Right

The example below demonstrates the use of ‘Utils::padRight‘ to left align the characters in a string by padding them on the right with a specified character, of a specified total length.

In this example, the default padding character is used to pad the string, which is a whitespace (‘ ‘).





		
		
			2. Pad Right
			
C++
			
			// Pad Right

// Declare string
std::string original = "<-Kenneth->";

// Get padding width
int width = 15;

// Display result
std::cout << "Original:   '" << original << "'" << std::endl;
std::cout << "Pad Right: '" << Utils::padRight(original, width) << "'";

// expected output:
/*
    Original:   '<-Kenneth->'
    Pad Right:  '<-Kenneth->    '
*/
			
				
					
				
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						// Pad Right
 
// Declare string
std::string original = "<-Kenneth->";
 
// Get padding width
int width = 15;
 
// Display result
std::cout << "Original:   '" << original << "'" << std::endl;
std::cout << "Pad Right: '" << Utils::padRight(original, width) << "'";
 
// expected output:
/*
    Original:   '<-Kenneth->'
    Pad Right:  '<-Kenneth->    '
*/

3. Pad Center

The example below demonstrates the use of ‘Utils::padCenter‘ to center align the characters in a string by padding them on the left and right with a specified character, of a specified total length.

In this example, the default padding character is used to pad the string, which is a whitespace (‘ ‘).





		
		
			3. Pad Center
			
C++
			
			// Pad Center

// Declare string
std::string original = "<-Kenneth->";

// Get padding width
int width = 15;

// Display result
std::cout << "Original:   '" << original << "'" << std::endl;
std::cout << "Pad Center: '" << Utils::padCenter(original, width) << "'";

// expected output:
/*
    Original:   '<-Kenneth->'
    Pad Center: '  <-Kenneth->  '
*/
			
				
					
				
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						// Pad Center
 
// Declare string
std::string original = "<-Kenneth->";
 
// Get padding width
int width = 15;
 
// Display result
std::cout << "Original:   '" << original << "'" << std::endl;
std::cout << "Pad Center: '" << Utils::padCenter(original, width) << "'";
 
// expected output:
/*
    Original:   '<-Kenneth->'
    Pad Center: '  <-Kenneth->  '
*/

4. Utils Namespace

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





		
		
			Utils Namespace
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Aug 2, 2021
//    Taken From: http://programmingnotes.org/
//    File:  Utils.h
//    Description: Handles general utility functions
// ============================================================================
#pragma once
#include <string>

namespace Utils {
    /**
    * FUNCTION: padLeft 
    * USE: Returns a new string that right aligns the characters in a 
    *   string by padding them on the left with a specified 
    *   character, of a specified total length
    * @param source: The source string
    * @param totalWidth: The number of characters to pad the source string
    * @param paddingChar: The padding character
    * @return: The modified source string left padded with as many paddingChar 
    *   characters needed to create a length of totalWidth
    */
    std::string padLeft(std::string source, std::size_t totalWidth, char paddingChar = ' ') {
        if (totalWidth > source.size()) {
            source.insert(0, totalWidth - source.size(), paddingChar);
        }
        return source;
    }

    /**
    * FUNCTION: padRight 
    * USE: Returns a new string that left aligns the characters in a 
    *   string by padding them on the right with a specified 
    *   character, of a specified total length
    * @param source: The source string
    * @param totalWidth: The number of characters to pad the source string
    * @param paddingChar: The padding character
    * @return: The modified source string right padded with as many paddingChar 
    *   characters needed to create a length of totalWidth
    */
    std::string padRight(std::string source, std::size_t totalWidth, char paddingChar = ' ') {
        if (totalWidth > source.size()) {
            source.insert(source.size(), totalWidth - source.size(), paddingChar);
        }
        return source;
    }

    /**
    * FUNCTION: padCenter 
    * USE: Returns a new string that center aligns the characters in a 
    *   string by padding them on the left and right with a specified 
    *   character, of a specified total length
    * @param source: The source string
    * @param totalWidth: The number of characters to pad the source string
    * @param paddingChar: The padding character
    * @return: The modified source string padded with as many paddingChar 
    *   characters needed to create a length of totalWidth
    */
    std::string padCenter(std::string source, std::size_t totalWidth, char paddingChar = ' ') {
        if (totalWidth > source.size()) {
            std::size_t totalPadWidth = totalWidth - source.size();
            std::size_t leftPadWidth = (totalPadWidth / 2) + source.size();
            source = padRight(padLeft(source, leftPadWidth, paddingChar), totalWidth, paddingChar);
        }
        return source;
    }
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Aug 2, 2021
//    Taken From: http://programmingnotes.org/
//    File:  Utils.h
//    Description: Handles general utility functions
// ============================================================================
#pragma once
#include <string>
 
namespace Utils {
    /**
    * FUNCTION: padLeft 
    * USE: Returns a new string that right aligns the characters in a 
    *   string by padding them on the left with a specified 
    *   character, of a specified total length
    * @param source: The source string
    * @param totalWidth: The number of characters to pad the source string
    * @param paddingChar: The padding character
    * @return: The modified source string left padded with as many paddingChar 
    *   characters needed to create a length of totalWidth
    */
    std::string padLeft(std::string source, std::size_t totalWidth, char paddingChar = ' ') {
        if (totalWidth > source.size()) {
            source.insert(0, totalWidth - source.size(), paddingChar);
        }
        return source;
    }
 
    /**
    * FUNCTION: padRight 
    * USE: Returns a new string that left aligns the characters in a 
    *   string by padding them on the right with a specified 
    *   character, of a specified total length
    * @param source: The source string
    * @param totalWidth: The number of characters to pad the source string
    * @param paddingChar: The padding character
    * @return: The modified source string right padded with as many paddingChar 
    *   characters needed to create a length of totalWidth
    */
    std::string padRight(std::string source, std::size_t totalWidth, char paddingChar = ' ') {
        if (totalWidth > source.size()) {
            source.insert(source.size(), totalWidth - source.size(), paddingChar);
        }
        return source;
    }
 
    /**
    * FUNCTION: padCenter 
    * USE: Returns a new string that center aligns the characters in a 
    *   string by padding them on the left and right with a specified 
    *   character, of a specified total length
    * @param source: The source string
    * @param totalWidth: The number of characters to pad the source string
    * @param paddingChar: The padding character
    * @return: The modified source string padded with as many paddingChar 
    *   characters needed to create a length of totalWidth
    */
    std::string padCenter(std::string source, std::size_t totalWidth, char paddingChar = ' ') {
        if (totalWidth > source.size()) {
            std::size_t totalPadWidth = totalWidth - source.size();
            std::size_t leftPadWidth = (totalPadWidth / 2) + source.size();
            source = padRight(padLeft(source, leftPadWidth, paddingChar), totalWidth, paddingChar);
        }
        return source;
    }
}// http://programmingnotes.org/

5. 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:   Aug 2, 2021
//    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 string
        std::string original = "<-Kenneth->";

        // Get padding width
        int width = 15;

        // Display result
        display("Original:   '" + original + "'");
        display("Pad Center: '" + Utils::padCenter(original, width) + "'");
        display("Pad Right:  '" + Utils::padRight(original, width) + "'");
        display("Pad Left:   '" + Utils::padLeft(original, width) + "'");
    } 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:   Aug 2, 2021
//    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 string
        std::string original = "<-Kenneth->";
 
        // Get padding width
        int width = 15;
 
        // Display result
        display("Original:   '" + original + "'");
        display("Pad Center: '" + Utils::padCenter(original, width) + "'");
        display("Pad Right:  '" + Utils::padRight(original, width) + "'");
        display("Pad Left:   '" + Utils::padLeft(original, width) + "'");
    } 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.

Monthly Archives: August 2021

C++ || How To Pad Left, Pad Right & Pad Center A String Of Fixed Length Using C++

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