ENTERPRISE SYSTEMS LAB-01 DATED: 06-06-2024 Note: If VS is not installed in lab, you can use online compiler or VS code. Online compilers 1. https://www.programiz.com/csharp-programming/online-compiler/ 2. https://www.w3schools.com/cs/cs_compiler.php 3. https://www.onlinegdb.com/online_csharp_compiler Sample Programs in C# Compile and run these programs to understand the working. Problem1: Checking Leap Year Write a C# program to check if a given year is a leap year or not. using System; class Program { static void Main(string[] args) { Console.Write("Enter a year: "); int year = Convert.ToInt32(Console.ReadLine()); if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) Console.WriteLine($"{year} is a leap year."); else Console.WriteLine($"{year} is not a leap year."); } } Problem2: Reverse a String Write a C# program to reverse a given string. using System; class Program { static void Main(string[] args) { 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); } } 3. Problem: Sum of Digits Write a C# program to calculate the sum of digits of a given number. using System; class Program { static void Main(string[] args) { 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); } } Problem4: Count Vowels in a String Write a C# program to count the number of vowels in a given string. using System; class Program { static void Main(string[] args) { Console.Write("Enter a string: "); string input = Console.ReadLine(); int vowelCount = 0; foreach (char c in input) { if ("aeiouAEIOU".Contains(c)) vowelCount++; } Console.WriteLine("Number of vowels: " + vowelCount); } } Problem5: Factorial Calculation Write a C# program to calculate the factorial of a given number. using System; class Program { static void Main(string[] args) { 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 of " + number + " is " + factorial); } } Tasks Q1: Write a C# program to check if a given string is a palindrome or not. (A palindrome is a string that reads the same backward as forward.) Q2: Write a C# program to calculate the sum of all even or odd numbers from 1 to a given number. Allow the user to choose whether to calculate the sum of even or odd numbers. Q3: Write a C# program to display the Fibonacci series up to a given number 'n'. The Fibonacci series is a series of numbers in which each number is the sum of the two preceding ones. Q4: Write a C# program to calculate the sum of the factorial of all numbers from 1 to a given number 'n'. The factorial of a number is the product of all positive integers less than or equal to that number. Q5: Write a C# program to count the frequency of each character in a given string and display the result. Ignore case sensitivity. (For example, in the string "hello", the frequency of 'l' is 2.)