1. using System; using System.Collections.Generic; using System.Linq; using System.Text;

namespace Csharp_exercises
{
class Program
{
static void Main(string[] args)
{

int x,y,z;

Console.Write("Enter value 1:"); x = int.Parse(Console.ReadLine());
Console.Write("Enter value 2:"); y = int.Parse(Console.ReadLine());
Console.Write("Enter value 3:"); z = int.Parse(Console.ReadLine());

if (x > y) if (x > z) Console.Write("The greatest value is:{0}.",x); else Console.Write("The greatest value is:{0}.", z); else if (y > z) Console.Write("The greatest value is:{0}.",y); else Console.Write("The greatest value is:{0}.",z);

Console.ReadLine(); } }
}

2. using System; using System.Collections.Generic; using System.Linq; using System.Text;

namespace Csharp_exercises
{
class Program
{
static void Main(string[] args)
{

float quiz_score; float mid_score; float final_score; float avg;
Console.Write("Enter quiz score:"); quiz_score=float.Parse(Console.ReadLine()); Console.Write("Enter mid-term score:"); mid_score = float.Parse(Console.ReadLine());
Console.Write("Enter final score:"); final_score = float.Parse(Console.ReadLine()); avg = (quiz_score +mid_score+final_score) / 3;

if (avg >= 90) Console.WriteLine("Grade A"); else if ((avg >= 70) && (avg < 90)) Console.WriteLine("Grade B"); else if ((avg >= 50) && (avg < 70)) Console.WriteLine("Grade C"); else if (avg < 50) Console.WriteLine("Grade F"); else Console.WriteLine("Invalid input");

Console.ReadLine(); } }
}

3. using System; using System.Collections.Generic; using System.Linq; using System.Text;

namespace Csharp_exercises
{
class Program
{
static void Main(string[] args)
{
char key;
Console.Write("Press a number key:"); key = (char)Console.Read(); switch (key)
{
case '0': Console.WriteLine("You pressed 0"); break; case '1': Console.WriteLine("You pressed 1"); break; case '2': Console.WriteLine("You pressed 2"); break; case '3': Console.WriteLine("You pressed 3"); break; case '4': Console.WriteLine("You pressed 4"); break; case '5': Console.WriteLine("You pressed 5"); break; case '6': Console.WriteLine("You pressed 6"); break; case '7': Console.WriteLine("You pressed 7"); break; case '8': Console.WriteLine("You pressed 8"); break; case '9': Console.WriteLine("You pressed 9"); break; default: Console.WriteLine("Not allowed!"); break;

}

} }
}

4. using System; using System.Collections.Generic; using System.Linq; using System.Text;

namespace Csharp_exercises
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("What is the correct way to declare a variable to store an integer value in C#?");
Console.WriteLine("a. int 1x=10");
Console.WriteLine("b. int x=10");
Console.WriteLine("c. float x=10.0f");
Console.WriteLine("d. string x=\"10\"");
Console.WriteLine("Choose the answer letter:"); char ans = (char)Console.read(); switch (ans)
{
case 'a':Console.WriteLine("Invalid choice!"); break; case 'b':Console.WriteLine("Congratulation!"); break; case 'c':Console.WriteLine("Invalid choice!"); break; case 'd':Console.WriteLine("Invalid choice!"); break; default:Console.WriteLine("Bad choice!");break;

}

}

}
}