C++ Exercises: Calculate the sum of the series 1.2+2.3+3.4+4.5+5.6+.....

Last update on April 07 2025 13:01:07 (UTC/GMT +8 hours)

67. Sum of Series 1.2 + 2.3 + 3.4 + ...

Write a program in C++ to calculate the sum of the series 1.2+2.3+3.4+4.5+5.6+.......

Sample Solution:-

C++ Code :

#include <iostream> // Include input/output stream library
using namespace std; // Use the standard namespace

int main() // Main function where the execution of the program starts
{
    int trm; // Declare an integer variable 'trm' to store the last term of the series
    double num, sum, i, m; // Declare double variables for calculations: num, sum, i (iteration), and m (multiplier)

    // Display a message to calculate the sum of a specific series
    cout << "\n\n calculate the sum of the series 1.2+2.3+3.4+4.5+5.6+......:\n";
    cout << "----------------------------------------------------------------\n";
    cout << " Input the last integer between 1 to 98 without fraction you want to add: ";
    cin >> trm; // Input the last term from the user

    sum = 0; // Initialize the sum to zero before starting the series calculation

    // Loop to calculate the series and print individual elements
    for (i = 1; i <= trm; i++) 
    {
        if (i < 9) 
        {
            m = .1; // Set the multiplier 'm' based on the value of 'i'
        }
        else 
        {
            m = .01; // Set the multiplier 'm' based on the value of 'i'
        }

        num = i + ((i + 1) * (m)); // Calculate each term of the series
        sum = sum + num; // Add the current term to the running sum
        cout << num; // Display the current term of the series

        if (i < trm) 
        {
            cout << " + "; // Display '+' between terms except for the last one
        }
    }

    cout << "\n The sum of the series = " << sum << endl; // Display the final sum of the series
}

Sample Output:

 calculate the sum of the series 1·2+2·3+3·4+4.5+5.6+......:           
----------------------------------------------------------------       
 Input the last integer between 1 to 98 without fraction you want to ad
d: 10                                                                  
1.2 + 2.3 + 3.4 + 4.5 + 5.6 + 6.7 + 7.8 + 8.9 + 9.1 + 10.11            
 The sum of the series =59.61

Flowchart:

For more Practice: Solve these Related Problems:

Write a C++ program to compute the sum of the series where each term is of the form n.(n+1) divided by 10, for n terms.
Write a C++ program that reads an integer and calculates the sum of the series: 1.2, 2.3, 3.4, ... using a loop.
Write a C++ program to iterate through numbers and sum the series defined by adding a decimal increment to each integer.
Write a C++ program that computes a series sum where each term is formed by concatenating the number with its successor as a decimal value.

C++ Code Editor:

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