Python Program to Calculate Sum of Natural Numbers.

Input: n = 5
Output: 15

Explanation:
1+2+3+4+5 = 15

• Take the input value n from the user.

• Initialize a variable S to 0 (to store the sum).

• Use a for loop to iterate from 1 to n. In each iteration, add the current number to S.

• Display the sum of n natural numbers as a result.

# Python code implementation to find sum of natural numbers
def sum_of_natural_numbers_with_loop(n):
    S = 0
    for i in range(1, n + 1):
        S += i
    return S

n = int(input("Enter the value of n: "))

result = sum_of_natural_numbers_with_loop(n)

print(f"Sum of the first {n} natural numbers using a loop is: {result}")

Enter the value of n: 10
sum of the first 10 natural numbers using a loop is: 55

Input: n = 10;
Output: 55

Explanation: 
sum = n*(n+1)/2
    = 10*(10+1)/2
    = 10*(11)/2
    = 10*5.5
    = 55

• Take the value of n as an input from the user.

• Initialize a variable sum to 0 to store the sum of natural numbers.

• Use the mathematical formula to calculate the sum and store the result in the sum variable.

• Display the value of the sum as a result. 

# Python sum of natural numbers
def sum_of_natural_numbers(n):
    S = (n * (n + 1)) // 2
    return S

n = int(input("Enter the value of n: "))

result = sum_of_natural_numbers(n)

print(f"Sum of the first {n} natural numbers is: {result}")