something

main.cs

using System.Runtime.InteropServices;
namespace ConsoleApp1 {
    class NewClass {
        public void printTwoNumbers() {
            Console.WriteLine("Enter the value of a: ");
            int a = int.Parse(Console.ReadLine());
            Console.WriteLine("Enter the value of b: ");
            int b = int.Parse(Console.ReadLine());

            Console.WriteLine("The sum of {0} and {1} is {2}", a, b, a + b);
        }

        public void simpleInterest() {
            Console.WriteLine("Enter the value of P: ");
            int principal = int.Parse(Console.ReadLine());
            Console.WriteLine("Enter the value of T: ");
            int time = int.Parse(Console.ReadLine());
            Console.WriteLine("Tnter the value of R: ");
            int rate = int.Parse(Console.ReadLine());

            Console.WriteLine("The interest for the given input is {0}", (principal * time * rate) / 100);
        }

        public void posNeg() {
            Console.WriteLine("Enter the value of a: ");
            int x = int.Parse(Console.ReadLine());

            if (x < 0) {
                Console.WriteLine("the number is negative");
            } else {
                Console.WriteLine("the number is positive");
            }
        }

        public void evenorodd() {
            Console.WriteLine("Enter the value of a: ");
            int x = int.Parse(Console.ReadLine());

            if (x % 2 ==  0) {
                Console.WriteLine("the number is even");
            } else {
                Console.WriteLine("the number is odd");
            }
        }

        public void allowanceCalculate() {
            Console.WriteLine("Enter your salary: ");
            int x = int.Parse(Console.ReadLine());

            double dearnessAllowance = 0.4;
            double houseAllowance = 0.2;

            Console.WriteLine((x * dearnessAllowance * houseAllowance) + x);
        }

        public void distanceCalculator() {
            Console.WriteLine("Enter the distance in kilometer: ");
            double distance = int.Parse(Console.ReadLine());

            double meter = 1000.0;
            double feet = 3280.84;
            double inches = 39370.08;
            double centimeter = 100000;

            Console.Write("the distance in meter is {0}, in feet is {1}, in inches is {2}, in centimeter is {3}", meter * distance, distance * feet, distance * inches, distance * centimeter);
        }

        public void sphereAreaVolume() {
            Console.WriteLine("Enter the radius of the sphere: ");
            float radius = float.Parse(Console.ReadLine());
            double phi = System.MathF.PI;
            double vol = (4 * phi * System.MathF.Cbrt(radius)) / 3;
            double area = 4 * phi * System.MathF.Sqrt(radius);

            Console.Write("The area and volume of sphere for the given radius is {0} and {1}", area, vol);
        }

        public void calculateSize() {
            Console.WriteLine($"Size of int: {Marshal.SizeOf(typeof(int))}");
            Console.WriteLine($"Size of float: {Marshal.SizeOf(typeof(float))}");
            Console.WriteLine($"Size of double: {Marshal.SizeOf(typeof(double))}");
            Console.WriteLine($"Size of byte: {Marshal.SizeOf(typeof(byte))}");
            Console.WriteLine($"Size of sbyte: {Marshal.SizeOf(typeof(sbyte))}");
            Console.WriteLine($"Size of decimal: {Marshal.SizeOf(typeof(decimal))}");
            Console.WriteLine($"Size of long: {Marshal.SizeOf(typeof(long))}");
            Console.WriteLine($"Size of ulong: {Marshal.SizeOf(typeof(ulong))}");
            Console.WriteLine($"Size of short: {Marshal.SizeOf(typeof(short))}");
            Console.WriteLine($"Size of ushort: {Marshal.SizeOf(typeof(ushort))}");
        }

        public void printEven() {
            for (int i = 1; i <= 100; i++) {
                Console.WriteLine("{0}", i);
            }
        }

        public void isMultiple() {
            int a = int.Parse(Console.ReadLine());
            int b = int.Parse(Console.ReadLine());

            if (a % b == 0)
                Console.WriteLine("is multiple");
            else
                Console.WriteLine("is multiple");
        }

        public void sumOfFraction() {
            Console.WriteLine("Enter the no of iteration: ");
            int n = int.Parse(Console.ReadLine());

            double sum = 0;
            for (int i = 1; i <= n; i++) {
                sum += 1/i;
            }

            Console.WriteLine("The sum is {0}", sum);
        }

        public void isEven() {
            Console.WriteLine("Enter the number to check: ");
            int n = int.Parse(Console.ReadLine());

            if (n % 2 == 0)
                Console.WriteLine("even");
            else
                Console.WriteLine("odd");
        }

        public void ageCalculator() {
            List<int> ageList = new List<int>();
            Console.WriteLine("Enter the age of Ram: ");
            int ram = int.Parse(Console.ReadLine());
            Console.WriteLine("Enter the age of Ajay: ");
            int ajay = int.Parse(Console.ReadLine());
            Console.WriteLine("Enter the age of Shyam: ");
            int shyam = int.Parse(Console.ReadLine());


            ageList.Add(ram);
            ageList.Add(ajay);
            ageList.Add(shyam);

            ageList.Sort();

            Console.WriteLine("the smallest among the three is {0}", ageList);
        }

        public void giveDiscount() {
            Console.WriteLine("Enter the no of item: ");
            int n = int.Parse(Console.ReadLine());

            double discount = 0;
            double sum = 0;

            for (int i = 0; i < n; i++) {
                Console.WriteLine("Enter the price of the item: ");
                int price = int.Parse(Console.ReadLine());
                Console.WriteLine("Enter the quantity of the item: ");
                int quantity= int.Parse(Console.ReadLine());

                double total = price * quantity;

                if (total > 1000) {
                    discount = 0.1;
                }

                sum += total;
            }

            Console.WriteLine("the total sum is {0}", sum);
        }

        public void basicCalc() {
            Console.WriteLine("Enter the first number: ");
            double a = double.Parse(Console.ReadLine());
            Console.WriteLine("Enter the second number: ");
            double b = double.Parse(Console.ReadLine());
            Console.WriteLine("Enter the operation to perform: ");
            string op = Console.ReadLine();

            double result = 0.0;

            switch(op) {
                case "+":
                    result = a + b;
                    break;
                case "-":
                    result = a - b;
                    break;
                case "*":
                    result = a * b;
                    break;
                case "/":
                    result = a / b;
                    break;
                default:
                    Console.WriteLine("invalid operator");
                    break;
            }
            Console.WriteLine("the result is {0}", result);
        }

        public void profitCalculator() {
            Console.WriteLine("Enter the cost price: ");
            double cp = double.Parse(Console.ReadLine());

            Console.WriteLine("Enter the selling price: ");
            double sp = double.Parse(Console.ReadLine());

            if ((sp - cp) > 0) {
                Console.WriteLine("profit of {0}", sp - cp);
            } else {
                Console.WriteLine("loss of {0}", sp - cp);
            }
        }

        public void bonusCalc() {
            Console.WriteLine("Enter the current year: ");
            int year = int.Parse(Console.ReadLine());
            Console.WriteLine("Enter the year employee joined: ");
            int join_year = int.Parse(Console.ReadLine());

            double bonus = 0.0;

            if ((year - join_year) > 3)
                bonus = 2500;
        }

        public void printNaturalSum() {
            Console.WriteLine("enter the iteration: ");
            int n = int.Parse(Console.ReadLine());

            int sum = 0;

            for (int i = 1; i <= n; i++) {
                sum += i;
            }
            Console.WriteLine("the sum is {0}", sum);
        }

        public void Fib() {
            Console.WriteLine("enter the value of n: ");
            int n = int.Parse(Console.ReadLine());

            if (n == 0) Console.WriteLine(0);
            if (n == 1) Console.WriteLine(1);

            int first = 0;
            int second = 1;

            Console.WriteLine(first);
            Console.WriteLine(second);

            for (int i = 0; i < n; i++) {
                int tmp = first + second;
                Console.WriteLine(tmp);
                first = second;
                second = tmp;
            }
        }

        public void sum() {
            int count = 0;
            int sum = 0;
            for (int i = 100; i < 200; i++) {
                if (i % 7 == 0)
                    count += 1;
                    sum += i;
            }
            Console.WriteLine("the count is {0} and sum is {1}", count, sum);
        }

        public void count() {
            Console.WriteLine("enter the digit: ");
            int num = int.Parse(Console.ReadLine());
            int count = 0;

            do {
                count++;
                num /= 10;
            } while (num != 0);
            Console.WriteLine("the no of digit is {0}", count);
        }

        static void sumOfDigit() {
            Console.WriteLine("enter the digit: ");
            int num = int.Parse(Console.ReadLine());
            int count = 0;
            int sum = 0;

            do {
                sum += num % 10;
                count++;
                num /= 10;
            } while (num != 0);
            Console.WriteLine("the no of digit is {0}", count);
            Console.WriteLine("the sum of digits of the given number is {0}", sum);
        }

        static int reverse(int num) {
            int result = 0;

            while (num != 0) {
                result = result * 10 + num % 10;
                num /= 10;
            }

            Console.WriteLine("the reverse of the number is {0}", result);
            return result;
        }

        static void isPalindrome() {
            Console.WriteLine("enter the digit: ");
            int num = int.Parse(Console.ReadLine());

            int reverse_num = reverse(num);

            if (reverse_num == num)
                Console.WriteLine("palindrome");
            else
                Console.WriteLine("not palindrome");
        }

        // public static void Main(string[] args) {
        //     isPalindrome();
        // }

    }
}