Day 53: Python Program to Find Sum of Series 1+1/2+1/3...+1/N

 def sum_of_series(n):

    if n <= 0:

        return "N should be a positive integer."

    

    total_sum = 0

    for i in range(1, n + 1):

        total_sum += 1 / i

    return total_sum

try:

    N = int(input("Enter a positive integer N: "))

    if N <= 0:

        print("Please enter a positive integer.")

    else:

        result = sum_of_series(N)

        print(f"The sum of the series for N={N} is: {result:.6f}")

except ValueError:

    print("Invalid input! Please enter a positive integer.")

    

#source code --> clcoding.com 

Code Explanation:

1. Function Definition:

def sum_of_series(n):

    if n <= 0:

        return "N should be a positive integer."

sum_of_series(n):

This function takes an integer n as input, which represents the number of terms in the series.

If n is not a positive integer, it returns a message prompting the user to provide a valid input.

2. Series Calculation:

    total_sum = 0

    for i in range(1, n + 1):

        total_sum += 1 / i

total_sum = 0:

Initializes a variable to store the cumulative sum of the series.

for i in range(1, n + 1):

Iterates over the range from 1 to n (inclusive) to compute each term of the series.

total_sum += 1 / i:

Adds the reciprocal of the current number i (1+𝑖) to the cumulative sum.

3. Return Statement:

    return total_sum

Returns the calculated sum of the series as a floating-point number.

4. Main Block (User Interaction):

try:

    N = int(input("Enter a positive integer N: "))

    if N <= 0:

        print("Please enter a positive integer.")

try-except Block:

Handles invalid input to ensure the program doesn't crash if the user enters non-integer values.

N = int(input(...)):

Prompts the user for input and converts it to an integer.

if N <= 0:

Checks if the user entered a positive integer. If not, a message is displayed.

5. Function Call and Output:

    else:

        result = sum_of_series(N)

        print(f"The sum of the series for N={N} is: {result:.6f}")

except ValueError:

    print("Invalid input! Please enter a positive integer.")

sum_of_series(N):

Calls the function with the user-provided value of N to compute the series sum.

Formatted Output ({result:.6f}):

Displays the result rounded to 6 decimal places for better readability.

except ValueError:

Catches non-integer inputs and prompts the user to enter a valid positive integer.

6. Example Execution:

Input:

Enter a positive integer N: 5

Execution:

The program calls sum_of_series(5).

The function calculates:

𝑆=1+1/2+1/3+1/4+1/5=2.283333

The result is returned and printed.

Output:

The sum of the series for N=5 is: 2.283333