C++ || How To Replace All Occurrences Of A String With Another String Using C++

December 07, 2020 admin No comments

The following is a module with functions which demonstrates how to replace all occurrences of a substring with another substring using C++.

1. Replace All

The example below demonstrates the use of ‘Utils::replaceAll‘ to replace all occurrences of an ‘oldValue’ string with a ‘newValue’ string.





		
		
			1. Replace All
			
C++
			
			// Replace All

// Declare string
std::string numbers = "1987 19 22 2009 2019 1991 28 31";

// Replace whitespace with a comma
std::string replaced = Utils::replaceAll(numbers, " ", ", ");

// Display the result
std::cout << "Original: " << numbers;
std::cout << "Replaced: " << replaced;

// expected output:
/*
    Original: 1987 19 22 2009 2019 1991 28 31
    Replaced: 1987, 19, 22, 2009, 2019, 1991, 28, 31
*/
			
				
					
				
					1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
				
						// Replace All
 
// Declare string
std::string numbers = "1987 19 22 2009 2019 1991 28 31";
 
// Replace whitespace with a comma
std::string replaced = Utils::replaceAll(numbers, " ", ", ");
 
// Display the result
std::cout << "Original: " << numbers;
std::cout << "Replaced: " << replaced;
 
// expected output:
/*
    Original: 1987 19 22 2009 2019 1991 28 31
    Replaced: 1987, 19, 22, 2009, 2019, 1991, 28, 31
*/

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 7, 2020
//    Taken From: http://programmingnotes.org/
//    File:  Utils.h
//    Description: Handles general utility functions
// ============================================================================
#pragma once
#include <string>

namespace Utils {
    /**
    * FUNCTION: replaceAll 
    * USE: Replaces all occurrences of the 'oldValue' string with the 
    *   'newValue' string
    * @param source: The source string
    * @param oldValue: The string to be replaced
    * @param newValue: The string to replace all occurrences of oldValue
    * @return: A new string with all occurrences replaced
    */
    std::string replaceAll(const std::string& source
        , const std::string& oldValue, const std::string& newValue) {
        if (oldValue.empty()) {
            return source;
        }
        std::string newString;
        newString.reserve(source.length());
        std::size_t lastPos = 0;
        std::size_t findPos;
        while (std::string::npos != (findPos = source.find(oldValue, lastPos))) {
            newString.append(source, lastPos, findPos - lastPos);
            newString += newValue;
            lastPos = findPos + oldValue.length();
        }
        newString += source.substr(lastPos);
        return newString;
    }
}// http://programmingnotes.org/
			
				
					
				
					1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
				
						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Dec 7, 2020
//    Taken From: http://programmingnotes.org/
//    File:  Utils.h
//    Description: Handles general utility functions
// ============================================================================
#pragma once
#include <string>
 
namespace Utils {
    /**
    * FUNCTION: replaceAll 
    * USE: Replaces all occurrences of the 'oldValue' string with the 
    *   'newValue' string
    * @param source: The source string
    * @param oldValue: The string to be replaced
    * @param newValue: The string to replace all occurrences of oldValue
    * @return: A new string with all occurrences replaced
    */
    std::string replaceAll(const std::string& source
        , const std::string& oldValue, const std::string& newValue) {
        if (oldValue.empty()) {
            return source;
        }
        std::string newString;
        newString.reserve(source.length());
        std::size_t lastPos = 0;
        std::size_t findPos;
        while (std::string::npos != (findPos = source.find(oldValue, lastPos))) {
            newString.append(source, lastPos, findPos - lastPos);
            newString += newValue;
            lastPos = findPos + oldValue.length();
        }
        newString += source.substr(lastPos);
        return newString;
    }
}// 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 7, 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 string
        std::string numbers = "1987 19 22 2009 2019 1991 28 31";

        // Replace whitespace with a comma
        std::string replaced = Utils::replaceAll(numbers, " ", ", ");

        // Display the result
        display("Original: " + numbers);
        display("Replaced: " + replaced);
    } 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/
			
				
					
				
					1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
				
						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Dec 7, 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 string
        std::string numbers = "1987 19 22 2009 2019 1991 28 31";
 
        // Replace whitespace with a comma
        std::string replaced = Utils::replaceAll(numbers, " ", ", ");
 
        // Display the result
        display("Original: " + numbers);
        display("Replaced: " + replaced);
    } 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.

Was this article helpful?

👍 YesNo

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

C++ || How To Replace All Occurrences Of A String With Another String Using C++

Related

Leave a ReplyCancel reply

Search

Compile Your Code Now

Translate Page

Popular Pages

Recent

Archives

Categories