A Switch is a selection statement, and it will execute a single case statement from the list of multiple case statements based on the pattern match with the defined expression.
Using the switch statement in c#, we can replace the functionality of the if…else if statement. A switch is easier to read (in most cases).
Each case statement must finish with a jump statement (that can be break or goto or return).
In other words, C# does not support “fall through” from one case statement to the next (which is a common source of unexpected behaviour (bugs) in other languages).
The default label is optional. If no default case is defined, then the default behaviour is to do nothing.
When C# reaches a break keyword, it breaks out of the switch block. This will stop the execution of more code and case testing inside the block.
You can also nest switch statements, although these can get hard to read.
Here is the basic syntax of the switch statement
Syntax
switch(expression)
{
case value1:
//Statements to Execute
break;
case value2:
//Statements to Execute
break;
case value3:
//Statements to Execute
break
......
default:
//code to be executed if all cases are not matched;
break;
}
Lets see a simple example of this
Example
In this example we create a console program that will ask a user to enter a number, depending on the number we will display a message.
We use a switch statement for this
using System;
public class Program
{
public static void Main()
{
Console.WriteLine("Enter a number:");
int num = Convert.ToInt32(Console.ReadLine());
switch (num)
{
case 10:
Console.WriteLine("It is 10");
break;
case 20:
Console.WriteLine("It is 20");
break;
case 30:
Console.WriteLine("It is 30");
break;
default:
Console.WriteLine("Another number");
break;
}
}
}
Here is a trial run
Enter a number: 20 It is 20
You can actually group cases together, lets adapt the previous example so that when the user enters 10, 20 or 30 the same message is displayed
using System;
public class Program
{
public static void Main()
{
Console.WriteLine("Enter a number:");
int num = Convert.ToInt32(Console.ReadLine());
switch (num)
{
case 10:
case 20:
case 30:
Console.WriteLine("You entered 10, 20 or 30");
break;
default:
Console.WriteLine("Another number");
break;
}
}
}
We can use enum values with Switch case statements to perform required operations. Here is an example of this
using System;
public class Program
{
public static void Main()
{
Season myseason = Season.Spring;
switch (myseason)
{
case Season.Spring:
Console.WriteLine("Spring");
break;
case Season.Summer:
Console.WriteLine("Summer");
break;
case Season.Autumn:
Console.WriteLine("Autumn");
break;
default:
Console.WriteLine("Winter");
break;
}
Console.WriteLine("Press Enter Key to Exit..");
Console.ReadLine();
}
public enum Season
{
Spring,
Summer,
Autumn,
Winter
}
}