Ifs and Switches

Here is the if and if else statement example

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace IfStatementExamples
{
    class Program
    {
        /// 

        /// This program just shows how to use if
        /// and if else statements
        /// it also shows how to use tryParse
        /// to catch errors in entry
        /// 
        /// 
        static void Main(string[] args)
        {
            //initialize the program
            Program p = new Program();
            //call the GetTemperature method
            p.GetTemperature();
            Console.ReadKey();
        }

        void GetTemperature()
        {
            //set the temp variable
            int temp=0;
            //prompt the user
            Console.WriteLine("Enter the Temperature.");
            //this is the try parse. 
            //if the value entered on the console is a
            //valid integer it returns true to isInt and assigns
            //the value to the "out" parameter temp
            //if not, it returns false and ignores the out parameter
            bool isInt = int.TryParse(Console.ReadLine(), out temp);

            //so if it isn't true we want to tell them
            //and give them one more chance to enter
            //a good value
            if (isInt != true)
            {
                Console.WriteLine("Enter a valid integer");
                temp = int.Parse(Console.ReadLine());
            }
            //call the ReactToTemp method and pass it the temperature
            ReactToTemp(temp);

        }

        void ReactToTemp(int temperature)
        {
            //this method uses if and else if to evaluate the temperature
            //and change the console background based on the temperature
            if (temperature >= 100 )
            {
                Console.BackgroundColor = ConsoleColor.Red;
                Console.Clear();
                Console.WriteLine("Hot");
            }
            else if (temperature >= 80)
            {
                Console.BackgroundColor = ConsoleColor.DarkYellow;
                Console.Clear();
                Console.WriteLine("Warm");
            }
            else if (temperature >= 60)
            {
                Console.BackgroundColor = ConsoleColor.Green;
                Console.Clear();
                Console.WriteLine("Pleasent");
            }
            else if (temperature >= 30)
            {
                Console.BackgroundColor = ConsoleColor.Blue;
                Console.Clear();
                Console.WriteLine("Cool");
            }
            else
            {
                Console.BackgroundColor = ConsoleColor.Cyan;
                Console.Clear();
                Console.WriteLine("cold");
            }
        }

    }
}

---

Here is the switch example

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SwitchExample
{
    class Program
    {
        /// 

        /// this program shows an example of a switch
        /// structure. It takes a grade as an integer
        /// and returns a letter grade
        /// 
        
        static void Main(string[] args)
        {
            //initialize the program
            Program p = new Program();
            //call the method GetGrade();
            p.GetGrade();
            Console.ReadKey();
        }

        void GetGrade()
        {
            //Declare the variable grade
            int grade;
            //prompt the user
            Console.WriteLine("Enter your grade");
            //use the try parse to test the input--see
            //the explanation on the if example
            bool goodGrade = int.TryParse(Console.ReadLine(), out grade);
            if (!goodGrade)
            {
                //in this case we don't give them a second chance
                //we just tell them what's wrong and exit
                Console.WriteLine("Next time do a valid grade as an integer");
                return;
            }
            //call translate grade
            TranslateGrade(grade);
        }

        void TranslateGrade(int grade)
        {
            //create a string variable for the letter grade
            //and give it a default value
            string letterGrade ="Unavailable";
            //set up the switch. Cases have to be
            //exact values. No ranges or > < 
            switch (grade)
            {
                    //case 4 means literally the grade must be 4 to match
                case 4: //note the colon here.
                    letterGrade="A";
                    break;
                case 3:
                    letterGrade = "B";
                    break;
                case 2:
                    letterGrade = "C";
                    break;
                case 1:
                    letterGrade = "D";
                    break;
                case 0:
                    letterGrade = "F";
                    break;
                default:
                    letterGrade = "Undefined";
                    break;
            }
            Console.WriteLine("Your Letter grade is {0}", letterGrade);
        }


    }
}