﻿ C# - Calculate the sum of the series 1+11+111+ 1111+ .. N

# C#: Calculate the sum of the series 1 +11 + 111 + 1111 + .. n terms

## C# Sharp For Loop: Exercise-26 with Solution

Write a program in C# Sharp to find the sum of the series 1 +11 + 111 + 1111 + .. n terms.

Visual Presentation:

Sample Solution:

C# Sharp Code:

``````using System;  // Importing necessary namespace

public class Exercise26  // Declaration of the Exercise26 class
{
public static void Main()  // Main method, entry point of the program
{
int n, i, sum = 0;  // Declaration of variables n, i, and sum as integers
int t = 1;  // Initializing t as 1

Console.Write("\n\n");  // Displaying new lines
Console.Write("Calculate the sum of the series 1 +11 + 111 + 1111 + .. n terms:\n");  // Displaying the purpose of the program
Console.Write("------------------------------------------------------------------");  // Displaying a separator
Console.Write("\n\n");  // Displaying new lines

Console.Write("Input the number of terms : ");  // Prompting the user to input the number of terms
n = Convert.ToInt32(Console.ReadLine());  // Reading the number of terms entered by the user

// Loop to generate the series and calculate its sum
for (i = 1; i <= n; i++)
{
Console.Write("{0} + ", t);  // Displaying the current term in the series
sum = sum + t;  // Calculating the sum of the series
t = (t * 10) + 1;  // Generating the next term in the series
}

Console.Write("\nThe Sum is : {0}\n", sum);  // Displaying the total sum of the series
}
}
```
```

Sample Output:

```Calculate the sum of the series 1 +11 + 111 + 1111 + .. n terms:
------------------------------------------------------------------
Input the numbe of terms : 6
1 + 11 + 111 + 1111 + 11111 + 111111 +
The Sum is : 123456
```

Flowchart:

C# Sharp Code Editor: