C#: Sum of first n natural numbers

Last update on December 20 2024 12:52:22 (UTC/GMT +8 hours)

Write a program in C# Sharp to find the sum of the first n natural numbers using recursion.

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Sample Solution:

C# Sharp Code:

using System;

// Class definition named 'RecExercise3'
class RecExercise3
{
    // Main method, the entry point of the program
    static void Main(string[] args)
    {
        // Display a description of the program
        Console.Write("\n\n Recursion : Sum of first n natural numbers :\n");
        Console.Write("--------------------------------------------------\n");
        Console.Write(" How many numbers to sum : ");
        int n = Convert.ToInt32(Console.ReadLine()); // Read the user input for the count of numbers to sum

        // Calculate and display the sum of the first 'n' natural numbers
        Console.Write(" The sum of first {0} natural numbers is : {1}\n\n", n, SumOfTen(1, n));
    }

    // Function to initiate the calculation of the sum
    static int SumOfTen(int min, int max)
    {
        return CalcuSum(min, max);
    }

    // Recursive function to calculate the sum of natural numbers from 'min' to 'val'
    static int CalcuSum(int min, int val)
    {
        // Base case: if the current value is equal to the minimum value, return the value itself
        if (val == min)
            return val;

        // Recursive call: Add the current value with the sum of previous values from 'min' to 'val-1'
        return val + CalcuSum(min, val - 1);
    }
}

Sample Output:

Recursion : Sum of first n natural numbers :                                                                 
--------------------------------------------------                                                            
 How many numbers to sum : 5                                                                                  
 The sum of first 5 natural numbers is : 15  

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