50 C# (C Sharp) For Loop programming questions and Solutions for Developers and college freshers

Written by: Idika Destiny

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Published 9 Months Ago On Wednesday, August 9, 2023
Updated 9 Months Ago On Wednesday, August 9, 2023
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Write a C# program to display numbers from 1 to 10 using a for loop.

for (int i = 1; i <= 10; i++)

{

    Console.WriteLine(i);

}


Write a C# program to calculate the sum of all even numbers between 1 and 20 using a for loop.

int sum = 0;

for (int i = 2; i <= 20; i += 2)

{

    sum += i;

}

Console.WriteLine("Sum: " + sum);


Write a C# program to print the multiplication table of a given number using a for loop.

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

for (int = 1; i <= 10; i++)

{

    Console.WriteLine($"{number} x {i} = {number * i}");

}


Write a C# program to calculate the factorial of a number using a for loop.

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

int factorial = 1;

for (int = 1; i <= numberi++)

{

    factorial *= i;

}

Console.WriteLine("Factorial: " + factorial);


Write a C# program to find the sum of all the digits of a given number using a for loop.

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

int sum = 0;

while (number > 0)

{

    sum += number % 10;

    number /= 10;

}

Console.WriteLine("Sum of digits: " + sum);


Write a C# program to check if a given number is prime using a for loop.

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

bool isPrime = true;

for (int i = 2; i <= Math.Sqrt(number); i++)

{

    if (number % i == 0)

    {

        isPrime = false;

        break;

    }

}

Console.WriteLine("Is Prime: " + isPrime);


Write a C# program to generate the Fibonacci series up to a given number using a for loop.

Console.Write("Enter the number of terms: ");

int n = Convert.ToInt32(Console.ReadLine());

int first = 0, second = 1;

Console.Write("Fibonacci Series: " + first + ", " + second);

for (int i = 2; i < n; i++)

{

    int next = first + second;

    Console.Write(", " + next);

    first = second;

    second = next;

}

Console.WriteLine();


Write a C# program to find the largest element in an array using a for loop.

int[] array = { 10, 5, 20, 15, 30 };

int max = array[0];

for (int i = 1; i < array.Length; i++)

{

    if (array[i] > max)

    {

        max = array[i];

    }

}

Console.WriteLine("Largest element: " + max);


Write a C# program to count the number of vowels in a given string using a for loop.

Console.Write("Enter a string: ");

string input = Console.ReadLine();

int count = 0;

string vowels = "aeiou";

for (int i = 0; i < input.Length; i++)

{

    if (vowels.Contains(input[i]))

    {

        count++;

    }

}

Console.WriteLine("Number of vowels: " + count);


Write a C# program to reverse a given string using a for loop.

Console.Write("Enter a string: ");

string input = Console.ReadLine();

string reversed = "";

for (int i = input.Length - 1; i >= 0; i--)

{

    reversed += input[i];

}

Console.WriteLine("Reversed string: " + reversed);


Write a C# program to find the sum of the digits of a given number until the sum becomes a single digit using a for loop.

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

while (number > 9)

{

    int sum = 0;

    while (number > 0)

    {

        sum += number % 10;

        number /= 10;

    }

    number = sum;

}

Console.WriteLine("Single digit sum: " + number);



Write a C# program to print the ASCII values of all the characters from A to Z using a for loop.

for (2 c = 'A'; c <= 'Z'; c++)

{

    Console.WriteLine($"{c}: {(int)c}");

}


Write a C# program to find the second largest element in an array using a for loop.

int[] array = { 10, 5, 20, 15, 30 };

int max = array[0];

int secondMax = int.MinValue;

for (int i = 1; i < array.Length; i++)

{

    if (array[i] > max)

    {

        secondMax = max;

        max = array[i];

    }

    else if (array[i] > secondMax && array[i] != max)

    {

        secondMax = array[i];

    }

}

Console.WriteLine("Second largest element: " + secondMax);


Write a C# program to check if a given string is a palindrome using a for loop.

Console.Write("Enter a string: ");

string input = Console.ReadLine();

bool isPalindrome = true;

for (int i = 0; i < input.Length / 2; i++)

{

    if (input[i] != input[input.Length - i - 1])

    {

        isPalindrome = false;

        break;

    }

}

Console.WriteLine("Is Palindrome: " + isPalindrome);


Write a C# program to count the occurrences of a specific character in a given string using a for loop.

Console.Write("Enter a string: ");

string input = Console.ReadLine();

Console.Write("Enter a character: ");

char character = Console.ReadLine()[0];

int count = 0;

for (int i = 0; i < input.Length; i++)

{

    if (input[i] == character)

    {

        count++;

    }

}

Console.WriteLine("Occurrences: " + count);


Write a C# program to find the GCD (Greatest Common Divisor) of two numbers using a for loop.

Console.Write("Enter the first number: ");

int number1 = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter the second number: ");

int number2 = Convert.ToInt32(Console.ReadLine());

int gcd = 1;

for (int i = 1; i <= number1 && i <= number2; i++)

{

    if (number1 % i == 0 && number2 % i == 0)

    {

        gcd = i;

    }

}

Console.WriteLine("GCD: " + gcd);


Write a C# program to check if a given number is an Armstrong number using a for loop.

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

int originalNumber = number;

int sum = 0;

int digitCount = (int)Math.Log10(number) + 1;

while (number > 0)

{

    int digit = number % 10;

    sum += (int)Math.Pow(digit, digitCount);

    number /= 10;

}

bool isArmstrong = sum == originalNumber;

Console.WriteLine("Is Armstrong: " + isArmstrong);


Write a C# program to find the LCM (Least Common Multiple) of two numbers using a for loop.

Console.Write("Enter the first number: ");

int number1 = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter the second number: ");

int number2 = Convert.ToInt32(Console.ReadLine());

int lcm = Math.Max(number1, number2);

while (true)

{

    if (lcm % number1 == 0 && lcm % number2 == 0)

    {

        break;

    }

    lcm++;

}

Console.WriteLine("LCM: " + lcm);


Write a C# program to generate a series of prime numbers between two given numbers using a for loop.

Console.Write("Enter the lower bound: ");

int lowerBound = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter the upper bound: ");

int upperBound = Convert.ToInt32(Console.ReadLine());

Console.Write("Prime numbers: ");

for (int number = lowerBound; number <= upperBound; number++)

{

    bool isPrime = true;

    for (int i = 2; i <= Math.Sqrt(number); i++)

    {

        if (number % i == 0)

        {

            isPrime = false;

            break;

        }

    }

    if (isPrime && number > 1)

    {

        Console.Write(number + " ");

    }

}

Console.WriteLine();


Write a C# program to calculate the sum of all odd numbers between two given numbers using a for loop.

Console.Write("Enter the lower bound: ");

int lowerBound = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter the upper bound: ");

int upperBound = Convert.ToInt32(Console.ReadLine());

int sum = 0;

for (int number = lowerBound; number <= upperBound; number++)

{

    if (number % 2 != 0)

    {

        sum += number;

    }

}

Console.WriteLine("Sum of odd numbers: " + sum);


Write a C# program to print the first n natural numbers using a for loop.

Console.Write("Enter the value of n: ");

int n = Convert.ToInt32(Console.ReadLine());

Console.Write("Natural numbers: ");

for (int i = 1; i <= n; i++)

{

    Console.Write(i + " ");

}

Console.WriteLine();


Write a C# program to find the sum of the first n natural numbers using a for loop.

Console.Write("Enter the value of n: ");

int n = Convert.ToInt32(Console.ReadLine());

int sum = 0;

for (int i = 1; i <= n; i++)

{

    sum += i;

}

Console.WriteLine("Sum: " + sum);


Write a C# program to print the first n even numbers using a for loop.

Console.Write("Enter the value of n: ");

int n = Convert.ToInt32(Console.ReadLine());

Console.Write("Even numbers: ");

for (int i = 1; i <= n; i++)

{

    Console.Write(2 * i + " ");

}

Console.WriteLine();


Write a C# program to calculate the sum of the squares of the first n natural numbers using a for loop.

Console.Write("Enter the value of n: ");

int n = Convert.ToInt32(Console.ReadLine());

int sum = 0;

for (int i = 1; i <= n; i++)

{

    sum += i * i;

}

Console.WriteLine("Sum of squares: " + sum);


Write a C# program to print the pattern:

*

**

***

****

*****

using a for loop.

Console.Write("Enter the number of rows: ");

int rows = Convert.ToInt32(Console.ReadLine());

for (int i = 1; i <= rows; i++)

{

    for (int j = 1; j <= i; j++)

    {

        Console.Write("*");

    }

    Console.WriteLine();

}


Write a C# program to print the pattern:

*****

****

***

**

*

using a for loop.

Console.Write("Enter the number of rows: ");

int rows = Convert.ToInt32(Console.ReadLine());

for (int i = rows; i >= 1; i--)

{

    for (int j = 1; j <= i; j++)

    {

        Console.Write("*");

    }

    Console.WriteLine();

}


Write a C# program to print the pattern:

    *

   **

  ***

 ****

*****

using a for loop.

Console.Write("Enter the number of rows: ");

int rows = Convert.ToInt32(Console.ReadLine());

for (int i = 1; i <= rows; i++)

{

    for (int j = 1; j <= rows - i; j++)

    {

        Console.Write(" ");

    }

    for (int k = 1; k <= i; k++)

    {

        Console.Write("*");

    }

    Console.WriteLine();

}


Write a C# program to print the pattern:

*****

 ****

  ***

   **

    *

using a for loop.

Console.Write("Enter the number of rows: ");

int rows = Convert.ToInt32(Console.ReadLine());

for (int i = 1; i <= rows; i++)

{

    for (int j = 1; j < i; j++)

    {

        Console.Write(" ");

    }

    for (int k = i; k <= rows; k++)

    {

        Console.Write("*");

    }

    Console.WriteLine();

}


Write a C# program to print the pattern:

    1

   121

  12321

 1234321

123454321

using a for loop.

Console.Write("Enter the number of rows: ");

int rows = Convert.ToInt32(Console.ReadLine());

for (int i = 1; i <= rows; i++)

{

    for (int j = 1; j <= rows - i; j++)

    {

        Console.Write(" ");

    }

    for (int k = 1; k <= i; k++)

    {

        Console.Write(k);

    }

    for (int l = i - 1; l >= 1; l--)

    {

        Console.Write(l);

    }

    Console.WriteLine();

}


Write a C# program to find the sum of the first n terms of the series: 1 + 1/2 + 1/3 + 1/4 + ... using a for loop.

Console.Write("Enter the value of n: ");

int n = Convert.ToInt32(Console.ReadLine());

double sum = 0;

for (int i = 1; i <= n; i++)

{

    sum += 1.0 / i;

}

Console.WriteLine("Sum: " + sum);


Write a C# program to calculate the average of the first n natural numbers using a for loop.

Console.Write("Enter the value of n: ");

int n = Convert.ToInt32(Console.ReadLine());

double sum = 0;

for (int i = 1; i <= n; i++)

{

    sum += i;

}

double average = sum / n;

Console.WriteLine("Average: " + average);


Write a C# program to find the sum of all prime numbers between two given numbers using a for loop.

Console.Write("Enter the lower bound: ");

int lowerBound = Convert.ToInt32(Console.ReadLine());

Console.Write("Enter the upper bound: ");

int upperBound = Convert.ToInt32(Console.ReadLine());

int sum = 0;

for (int number = lowerBound; number <= upperBound; number++)

{

    bool isPrime = true;

    for (int i = 2; i <= Math.Sqrt(number); i++)

    {

        if (number % i == 0)

        {

            isPrime = false;

            break;

        }

    }

    if (isPrime && number > 1)

    {

        sum += number;

    }

}

Console.WriteLine("Sum of prime numbers: " + sum);


Write a C# program to find the sum of the digits of a given number using a for loop (without using division or modulus operator).

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

int sum = 0;

while (number > 0)

{

    sum += number - (number / 10) * 10;

    number /= 10;

}

Console.WriteLine("Sum of digits: " + sum);


Write a C# program to find the reverse of a given number using a for loop.

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

int reverse = 0;

while (number > 0)

{

    reverse = reverse * 10 + number % 10;

    number /= 10;

}

Console.WriteLine("Reversed number: " + reverse);


Write a C# program to check if a given number is a palindrome using a for loop (without converting to a string).

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

int originalNumber = number;

int reverse = 0;

while (number > 0)

{

    reverse = reverse * 10 + number % 10;

    number /= 10;

}

bool isPalindrome = reverse == originalNumber;

Console.WriteLine("Is Palindrome: " + isPalindrome);


Write a C# program to check if a given string is a palindrome using a for loop (case-insensitive and ignoring spaces).

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

string strippedInput = input.Replace(" ", "").ToLower();

bool isPalindrome = true;

for (int i = 0; i < strippedInput.Length / 2; i++)

{

    if (strippedInput[i] != strippedInput[strippedInput.Length - i - 1])

    {

        isPalindrome = false;

        break;

    }

}

Console.WriteLine("Is Palindrome: " + isPalindrome);


Write a C# program to find the factorial of a given number using a for loop.

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

int factorial = 1;

for (int i = 1; i <= number; i++)

{

    factorial *= i;

}

Console.WriteLine("Factorial: " + factorial);


Write a C# program to find the Fibonacci series up to a given number using a for loop.

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

int a = 0;

int b = 1;

Console.Write("Fibonacci series: " + a + " " + b + " ");

for (int i = 3; i <= number; i++)

{

    int c = a + b;

    Console.Write(c + " ");

    a = b;

    b = c;

}

Console.WriteLine();


Write a C# program to find the number of digits in a given number using a for loop.

Console.Write("Enter a number: ");

int number = Convert.ToInt32(Console.ReadLine());

int digitCount = 0;

while (number != 0)

{

    number /= 10;

    digitCount++;

}

Console.WriteLine("Number of digits: " + digitCount);


Write a C# program to find the largest element in an array using a for loop.

int[] array = { 10, 5, 20, 15, 30 };

int max = array[0];

for (int i = 1; i < array.Length; i++)

{

    if (array[i] > max)

    {

        max = array[i];

    }

}

Console.WriteLine("Largest element: " + max);


Write a C# program to count the number of even and odd elements in an array using a for loop.

int[] array = { 10, 5, 20, 15, 30 };

int evenCount = 0;

int oddCount = 0;

for (int i = 0; i < array.Length; i++)

{

    if (array[i] % 2 == 0)

    {

        evenCount++;

    }

    else

    {

        oddCount++;

    }

}

Console.WriteLine("Even count: " + evenCount);

Console.WriteLine("Odd count: " + oddCount);


Write a C# program to find the sum of all elements in a 2D array using a for loop.

int[,] array = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } };

int sum = 0;

for (int i = 0; i < array.GetLength(0); i++)

{

    for (int j = 0; j < array.GetLength(1); j++)

    {

        sum += array[i, j];

    }

}

Console.WriteLine("Sum: " + sum);


Write a C# program to find the transpose of a matrix using a for loop.

int[,] matrix = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } };

int rows = matrix.GetLength(0);

int columns = matrix.GetLength(1);

int[,] transpose = new int[columns, rows];

for (int i = 0; i < rows; i++)

{

    for (int j = 0; j < columns; j++)

    {

        transpose[j, i] = matrix[i, j];

    }

}

Console.WriteLine("Original matrix:");

for (int i = 0; i < rows; i++)

{

    for (int j = 0; j < columns; j++)

    {

        Console.Write(matrix[i, j] + " ");

    }

    Console.WriteLine();

}

 Console.WriteLine("Transposed matrix:");

for (int i = 0; i < columns; i++)

{

    for (int j = 0; j < rows; j++)

    {

         Console.Write(transpose[i, j] + " ");

    }

     Console.WriteLine();

}


Write a C# program to check if a given matrix is symmetric using a for loop.

int[,] matrix = { { 1, 2, 3 }, { 2, 4, 5 }, { 3, 5, 6 } };

bool isSymmetric = true;

int rows = matrix.GetLength(0);

int columns = matrix.GetLength(1);

for (int i = 0; i < rows; i++)

{

    for (int j = 0; j < columns; j++)

    {

        if (matrix[i, j] != matrix[j, i])

        {

            isSymmetric = false;

            break;

        }

    }

    if (!isSymmetric)

    {

        break;

    }

}

 Console.WriteLine("Is symmetric: " + isSymmetric);


Write a C# program to find the sum of elements in the main diagonal of a matrix using a for loop.

int[,] matrix = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } };

int sum = 0;

int size = matrix.GetLength(0);

for (int i = 0; i < size; i++)

{

    sum += matrix[i, i];

}

 Console.WriteLine("Sum of main diagonal elements: " + sum);


Write a C# program to find the sum of elements in the secondary diagonal of a matrix using a for loop.

int[,] matrix = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } };

int sum = 0;

int size = matrix.GetLength(0);

for (int i = 0; i < size; i++)

{

    sum += matrix[i, size - i - 1];

}

 Console.WriteLine("Sum of secondary diagonal elements: " + sum);


Write a C# program to find the number of vowels and consonants in a given string using a for loop.

 Console.Write("Enter a string: ");

string input = Console.ReadLine();

int vowelCount = 0;

int consonantCount = 0;

string vowels = "aeiouAEIOU";

for (int i = 0; i < input.Length; i++)

{

    if (Char.IsLetter(input[i]))

    {

        if (vowels.Contains(input[i]))

        {

            vowelCount++;

        }

        else

        {

            consonantCount++;

        }

    }

}

 Console.WriteLine("Vowel count: " + vowelCount);
 Console.WriteLine("Consonant count: " + consonantCount);


Write a C# program to count the number of occurrences of a given character in a string using a for loop.

 Console.Write("Enter a string: ");

string input = Console.ReadLine();

 Console.Write("Enter a character: ");

char character = Convert.ToChar(Console.ReadLine());

int count = 0;

for (int i = 0; i < input.Length; i++)

{

    if (input[i] == character)

    {

        count++;

    }

}

 Console.WriteLine("Occurrences of " + character + ": " + count);


Write a C# program to find the length of the longest word in a given sentence using a for loop.

 Console.Write("Enter a sentence: ");

string sentence = Console.ReadLine();

string[] words = sentence.Split(' ');

int maxLength = 0;

for (int i = 0; i < words.Length; i++)

{

    if (words[i].Length > maxLength)

    {

        maxLength = words[i].Length;

    }

}

 Console.WriteLine("Length of longest word: " + maxLength);


Write a C# program to check if a given string is a pangram (contains all letters of the alphabet) using a for loop.

 Console.Write("Enter a string: ");

string input = Console.ReadLine().ToLower();

bool[] letters = new bool[26];

for (int i = 0; i < input.Length; i++)

{

    if (Char.IsLetter(input[i]))

    {

        letters[input[i] - 'a'] = true;

    }

}

bool isPangram = true;

for (int i = 0; i < letters.Length; i++)

{

    if (!letters[i])

    {

        isPangram = false;

        break;

    }

}

 Console.WriteLine("Is pangram: " + isPangram);



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