C#: Enter the three numbers. Check to see that there is 3 sides of a triangle are not. If that is right, then see what kind of triangle.

//Enter the number 3. Check to see that there is 3 sides of a triangle are not. If that is right, then see what kind of triangle.
Source code:

class Program{

        static void Main() {

            float x, y, z;

            Console.Write("Input x: ");

            x = float.Parse(Console.ReadLine());

            Console.Write("Input y: ");

            y = float.Parse(Console.ReadLine());

            Console.Write("Input z: ");

            z = float.Parse(Console.ReadLine());

            if (x <= 0 || y <= 0 || z <= 0 || x + y <= z || y + z <= x || x + z <= y)

                Console.WriteLine("Input wrong !");

            else {

                if ((x == y && x * x * 2 == z * z) || (x == z && x * x * 2 == y * y) || (y == z && y * y * 2 == x * x))

                    Console.WriteLine("Triangle Square Scales");

                else {

                    if (x == y && y == z && z == x)

                        Console.WriteLine("Equilateral triangle");

                    else {

                        if (x == y || y == z || z == x)

                            Console.WriteLine("Isosceles triangle");

                        else

                            Console.WriteLine("Triangle");

                    }

                }

            }

            Console.ReadLine();

        }

}

C#: Enter the integer n has 4 digits. Looking for big numbers second.

//Enter the integer n has 4 digits. Looking for big numbers second.
//Example: n=2071. The number big number second is 2
Source code:

class Program{

        static void Main(){           

            int n;

            int[] arr = new int[4];

            do

            {

                Console.Write("Input n has 4 digits: ");

                n = int.Parse(Console.ReadLine());

            } while (n < 1000 || n > 9999);           

            for (int i = 0; i < 4; i++){

                arr[i] = n % 10;

                n = n / 10;

            }

            for (int i = 0; i < 3; i++)

                for (int j = i+1; j < 4;j++)

                    if (arr[i] => arr[j]){

                        int temp = arr[i];

                        arr[i] = arr[j];

                        arr[j] = temp;

                    }            

            Console.WriteLine("The second big number is: {0}", arr[2]);   

            Console.ReadLine();

        }

}

C#: Calculate the sum of digits of N have 8 digits

/*  Enter an integer n has 8 digits. Take a look: 
- The total value of the digits 
- The value of the total unit 
- The average of the total   */
Source code:

class Program{

static void Main(){

            int n;

            Console.Write("Input n has 8 digits: ");

            n = int.Parse(Console.ReadLine());

            //The total value of the digits

            int s = 0;

            int balance;

            int first = n;

            while (n != 0) {

                balance = n % 10;

                s += balance;

                n /= 10;

            }

            //The value of the total unit

            int unit;

            unit = s % 10;

            //The average of the total

            double avg;

            avg = (double) s / 8;

            Console.WriteLine("The total value of the digits {0} is: {1}",first,s);

            Console.WriteLine("The value of the total unit {0} is: {1}",s,unit);

            Console.WriteLine("The average of the total {0} is: {1}",s,avg);

            Console.ReadLine();

        }

}

C#: Check Prime Number !

//Write program with Console Application type, enter the number N from the keyboard. Check whether n is prime no.
Source code:

class Program{

        static void Main(string[] args)

        {

            int n;

            bool prime = true;

            Console.Write("Input n: ");

            n = int.Parse(Console.ReadLine());           

            if (n <= 1) prime = false;

            else {

                if (n == 2) prime = true;

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

                    if (n % i == 0) { prime = false; break; }

                    else prime = true;

            }

            if (prime == true) Console.WriteLine("{0} is prime no",n);

            else Console.WriteLine("{0} is not prime number", n);

            Console.ReadLine();

        }

    }