C++ Program to Calculate Sum of Natural Numbers

Source Code

#include <iostream>

using namespace std;

int main()
{
    int n; // Declare a variable to hold the number of natural numbers
    int sum = 0; // Declare a variable to hold the sum and initialize it to 0

    cout << "Enter the number of natural numbers: "; // Prompt the user to enter the number of natural numbers
    cin >> n; // Read the number from the standard input stream

    // Calculate the sum of the first n natural numbers
    for (int i = 1; i <= n; i++)
        sum += i;

    cout << "The sum of the first " << n << " natural numbers is: " << sum << endl; // Print the sum

    return 0;
}

Code Explanation

This program declares a variable n of type int to hold the number of natural numbers, and a variable sum of type int to hold the sum of the natural numbers. It then uses the cout object to print a prompt asking the user to enter the number of natural numbers, and the cin object to read the number from the standard input stream.

To calculate the sum of the natural numbers, the program uses a for loop to iterate over the range [1, n] and add each number to the sum. The loop variable i is initialized to 1, and the loop continues as long as i is less than or equal to n. The loop variable is incremented by 1 on each iteration.

Finally, the program uses the cout object to print the value of sum, which is the sum of the first n natural numbers.

What is a Natural Number?

In mathematics, a natural number is a positive integer, that is, a number that is greater than 0. The set of natural numbers is represented by the symbol N and is defined as:

Copy codeN = {1, 2, 3, 4, 5, ...}

The natural numbers are also known as the counting numbers or the positive integers. They are used to represent the number of objects in a set, and are often used to count the number of elements in a list or array.

The natural numbers are usually denoted by the letters n, m, or k, and are often used as indices or loop variables in programming.

Note: C++ All Examples