C#: Generate all possible permutations of an array

Last update on December 20 2024 12:52:19 (UTC/GMT +8 hours)

Write a program in C# Sharp to generate all possible permutations of an array using recursion.

Visual Presentation:

Sample Solution:

C# Sharp Code:

using System;

// Class formPermut contains methods to perform permutation operations
class formPermut
{
    // Method to swap two numbers using pass-by-reference
    public void swapTwoNumber(ref int a, ref int b)
    {
        int temp = a;
        a = b;
        b = temp;
    }

    // Method to generate permutations of elements in the array
    public void prnPermut(int[] list, int k, int m)
    {
        int i;
        // If k equals m, it signifies a complete permutation
        if (k == m)
        {
            for (i = 0; i <= m; i++)
                Console.Write("{0}", list[i]); // Print the permutation
            Console.Write(" "); // Space after each permutation
        }
        else
        {
            // Loop to generate permutations
            for (i = k; i <= m; i++)
            {
                swapTwoNumber(ref list[k], ref list[i]); // Swap elements at positions k and i
                prnPermut(list, k + 1, m); // Recursively generate permutations for the remaining elements
                swapTwoNumber(ref list[k], ref list[i]); // Restore the original order for backtracking
            }
        }
    }
}

// Main class RecExercise11 to execute permutation generation
class RecExercise11
{
    public static void Main()
    {
        int n, i;
        formPermut test = new formPermut();
        int[] arr1 = new int[5];

        Console.WriteLine("\n\n Recursion : Generate all possible permutations of an array :");
        Console.WriteLine("------------------------------------------------------------------");

        // Accept user input for the number of elements in the array
        Console.Write(" Input the number of elements to store in the array [maximum 5 digits]: ");
        n = Convert.ToInt32(Console.ReadLine());
        Console.Write(" Input {0} number of elements in the array:\n", n);

        // Accept user input for array elements
        for (i = 0; i < n; i++)
        {
            Console.Write(" element - {0} : ", i);
            arr1[i] = Convert.ToInt32(Console.ReadLine());
        }

        // Display generated permutations of the array elements
        Console.Write("\n The Permutations with a combination of {0} digits are: \n", n);
        test.prnPermut(arr1, 0, n - 1);
        Console.Write("\n\n");
    }
}

Sample Output:

Recursion : Generate all possible permutations of an array :                                                 
------------------------------------------------------------------                                            
 Input the number of elements to store in the array [maximum 5 digits ] :3                                    
 Input 3 number of elements in the array :                                                                    
 element - 0 : 1                                                                                              
 element - 1 : 2                                                                                              
 element - 2 : 3                                                                                              
                                                                                                              
 The Permutations with a combination of 3 digits are :                                                        
123 132 213 231 321 312

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