Daily Archives: February 9, 2021
C++ || How To Shuffle & Randomize A Vector Using C++
The following is a module with functions which demonstrates how to randomize and shuffle the contents of a vector using C++.
The following template function is a wrapper for the std::shuffle function.
1. Shuffle – Integer Vector
The example below demonstrates the use of ‘Utils::shuffle‘ to randomize an integer vector.
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// Shuffle - Integer Vector // Declare numbers std::vector<int> numbers = { 1987, 19, 22, 2009, 2019, 1991, 28, 31 }; // Get results auto results = Utils::shuffle(numbers); // Display results for (const auto& item : results) { std::cout << item << std::endl; } // example output: /* 28 1991 22 1987 19 2019 2009 31 */ |
2. Shuffle – String Vector
The example below demonstrates the use of ‘Utils::shuffle‘ to randomize a string vector.
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// Shuffle - String Vector // Declare names std::vector<std::string> names = { "Kenneth", "Jennifer", "Lynn", "Sole" }; // Get results auto results = Utils::shuffle(names); // Display results for (const auto& item : results) { std::cout << item << std::endl; } // example output: /* Jennifer Sole Kenneth Lynn */ |
3. Shuffle – Custom Object Vector
The example below demonstrates the use of ‘Utils::shuffle‘ to randomize a custom object vector.
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// Shuffle - Custom Object Vector // Declare object struct Person { int id; std::string name; }; // Declare names std::vector<Person> people = { {31, "Kenneth"}, {28, "Jennifer"}, {87, "Lynn"}, {91, "Sole"}, {22, "Kenneth"}, {19, "Jennifer"} }; // Get results auto results = Utils::shuffle(people); // Display results for (const auto& item : results) { std::cout << item.id << " - " << item.name << std::endl; } // example output: /* 28 - Jennifer 19 - Jennifer 22 - Kenneth 87 - Lynn 91 - Sole 31 - Kenneth */ |
4. Utils Namespace
The following is the Utils Namespace. Include this in your project to start using!
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// ============================================================================ // Author: Kenneth Perkins // Date: Feb 9, 2021 // Taken From: http://programmingnotes.org/ // File: Utils.h // Description: Handles general utility functions // ============================================================================ #pragma once #include <vector> #include <random> #include <chrono> #include <algorithm> namespace Utils { /** * FUNCTION: shuffle * USE: Shuffles a collection and returns the results * @param source: The collection to shuffle * @return: A new collection of shuffled items from the source */ template<typename T> std::vector<T> shuffle(std::vector<T> source) { auto seed = static_cast<std::mt19937::result_type> ( std::chrono::system_clock::now().time_since_epoch().count() ); std::mt19937 generator(seed); std::shuffle(source.begin(), source.end(), generator); 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!
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// ============================================================================ // Author: Kenneth Perkins // Date: Feb 9, 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 <vector> #include "Utils.h" void display(const std::string& message); // Declare object struct Person { int id; std::string name; }; int main() { try { // Declare numbers std::vector<int> numbers = { 1987, 19, 22, 2009, 2019, 1991, 28, 31 }; // Get results auto results = Utils::shuffle(numbers); // Display results for (const auto& item : results) { std::cout << item << std::endl; } display(""); // Declare names std::vector<std::string> names = { "Kenneth", "Jennifer", "Lynn", "Sole" }; // Get results auto results2 = Utils::shuffle(names); // Display results for (const auto& item : results2) { std::cout << item << std::endl; } display(""); // Declare names std::vector<Person> people = { {31, "Kenneth"}, {28, "Jennifer"}, {87, "Lynn"}, {91, "Sole"}, {22, "Kenneth"}, {19, "Jennifer"} }; // Get results auto results3 = Utils::shuffle(people); // Display results for (const auto& item : results3) { std::cout << item.id << " - " << item.name << std::endl; } } 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.
