YouTipCsharp Switch
[ C# Decision Making](#)
A **switch** statement allows testing a variable against multiple values. Each value is called a case, and the variable being tested is checked against each **switch case**.
The syntax for the **switch** statement in C# is:
switch(expression){ case constant-expression : statement(s); break; case constant-expression : statement(s); break; /* You can have any number of case statements */ default : /* Optional */ statement(s); break; }
The **switch** statement must follow these rules:
* The **expression** in a **switch** statement must be of an integer or enum type, or a class type that has a single conversion function to convert it to an integer or enum type.
* You can have any number of case statements within a switch. Each case is followed by the value to be compared 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.
* When the variable being tested matches a case's constant, the statements following that case are executed until a **break** statement is encountered.
* When a **break** statement is encountered, 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 a case statement is empty, it can omit the **break**, and the flow will _fall through_ to the next case until a break is encountered.
* C# does not allow fall-through from one case section to the next. If a case statement has been executed, it must contain a **break** or another jump statement.
* A **switch** statement can have an optional **default** case at the end. The default case is used to perform a task when none of the cases are true. It is good practice to include a **break** statement in the default case as well.
* C# does not support explicit fall-through from one case label to another. To enable explicit fall-through from one case label to another in C#, you can use `goto` a switch-case or `goto default`.
The following example is used to determine the current day of the week:
## Example
using System;
namespace MyApplication
{
class Program
{
static void Main(string[] args)
{
int day =4;
switch(day)
{
case 1:
Console.WriteLine("Monday");
break;
case 2:
Console.WriteLine("Tuesday");
break;
case 3:
Console.WriteLine("Wednesday");
break;
case 4:
Console.WriteLine("Thursday");
break;
case 5:
Console.WriteLine("Friday");
break;
case 6:
Console.WriteLine("Saturday");
break;
case 7:
Console.WriteLine("Sunday");
break;
}
}
}
}
The execution result varies depending on the current date. The result for the day I executed this is:
Thursday
The following example evaluates a student's grade and includes a **default** statement:
## Example
using System;
namespace DecisionMaking
{
class Program
{
static void Main(string[] args)
{
/* Local variable definition */
char grade ='B';
switch(grade)
{
case'A':
Console.WriteLine("Excellent!");
break;
case'B':
case'C':
Console.WriteLine("Well done");
break;
case'D':
Console.WriteLine("You passed");
break;
case'F':
Console.WriteLine("Better try again");
break;
default:
Console.WriteLine("Invalid grade");
break;
}
Console.WriteLine("Your grade is {0}", grade);
Console.ReadLine();
}
}
}
When the above code is compiled and executed, it produces the following result:
Well doneYour grade is B
[ C# Decision Making](#)