C# Switch Statement

Loops can execute a block of code as long as a specified condition is reached. Loops can be handy as they save time reducing errors and making code more readable.

C# While Loop

The while loop loops through a block of code as long as a specified condition is True. This loop starts with the while keyword, it must include a Boolean conditional expression inside brackets that returns either true or false. It executes code block until specified conditional expression returns false.

Syntax

while (condition)
{
   // code block to be executed
}

In the example given below, code in loop will run over again and again as long as a variable(i) is less than 10:

int  I = 0;
while( i < 10)
{
     Console.WriteLine(i);
     i++;
}

Note: We must not forget to increase the variable used in the condition, otherwise loop will never end.

Some rules  apply to a switch statement in c#

• The expression used in a switch statement must have an integral or enumerated type, or be of a class type in which the class has a single conversion function to an integral or enumerated type.
• We can  any number of case statements within a switch. Each case is followed by the value to be compared to and a colon.
• The constant-expression for a case must be the same data type as the variable in the switch, and it must be a constant or a literal.
• When the variable being switched on is equal to a case, the statements following that case will execute until a break statement is reached.
• When a break statement is reached, the switch terminates, and the flow of control jumps to the next line following the switch statement.
• Not every case needs to contain a break. If no break appears, then it will raise a compile time error.
• A switch statement can have an optional default case, which must appear at the end of the switch. The default case can be used for performing a task when none of the cases is true.

Example

using System;
public class Program
{
 public static void Main()
 {
      int weekId = 2;
      string weekName="";
       switch (weekId) {
            case 1:
                weekName="Sunday";
                Console.WriteLine("This is, {0}",weekName);
                break;
            case 2:
                weekName="Monday";
                Console.WriteLine("This is, {0}",weekName);
                break;
             case 3:
               weekName="Tuesday";
               Console.WriteLine("This is, {0}",weekName);
               break;
             case 4:
               weekName="Wednesday";
               Console.WriteLine("This is, {0}",weekName);
               break;
             case 5:
               weekName="Thursday";
               Console.WriteLine("This is, {0}",weekName);
               break;
             case 6:
               weekName="Friday";
               Console.WriteLine("This is, {0}",weekName);
               break;
               default:
               Console.WriteLine("Saturday");
               break;
         }
       Console.ReadLine();
   }
}

output

This is Monday

C# switch statement string

string color = "green";

switch (color)
{
    case "red":
        Console.WriteLine("The color is red.");
        break;
    case "green":
        Console.WriteLine("The color is green.");
        break;
    case "blue":
        Console.WriteLine("The color is blue.");
        break;
    default:
        Console.WriteLine("The color is unknown.");
        break;
}