switch statement in C#

                                                                                                                                                                                            Previous....

                                                                                                                                                                                                            Next...

A switch statement allows a variable to be tested for equality against a list of values. Each value is called a case, and the variable being switched on is checked for each switch case.

Syntax:

The syntax for a switch statement in C# is as follows:

switch(expression){
    case constant-expression  :
       statement(s);
       break; /* optional */
    case constant-expression  :
       statement(s);
       break; /* optional */
  
    /* you can have any number of case statements */
    default : /* Optional */
       statement(s);
}

The following rules apply to a switch statement:

• 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.
• You can have 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, the flow of control will fall throughto subsequent cases until a break is reached.
• 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. Nobreak is needed in the default case.

Flow Diagram:

Example:

using System;
 
namespace Switch_Case
{
  class Program
   {
     static void Main(string[] args)
      {
        int opt, num1, num2;
        float result;
 
        label:
 
        Console.WriteLine("\n\tMenu");
        Console.WriteLine("\nPress 1 for add");
        Console.WriteLine("Press 2 for subtraction");
        Console.WriteLine("Press 3 for multiplication");
        Console.WriteLine("Press 4 for Division");
  
        Console.Write("\n\nEnter first number:\t");
        num1 = Convert.ToInt32(Console.ReadLine());
 
        Console.Write("Enter second number:\t");
        num2 = Convert.ToInt32(Console.ReadLine());
 
        Console.Write("\nEnter your option:\t");
        opt = Convert.ToInt32(Console.ReadLine());
 
        switch (opt)
         {
           case 1:
               result = num1 + num2;
               Console.WriteLine("\n{0} + {1} = {2}", num1,                num2, result);
               break;
 
           case 2:
               result = num1 - num2;
               Console.WriteLine("\n{0} - {1} = {2}", num1,                num2, result);
               break;
           case 3:
               result = num1 * num2;
               Console.WriteLine("\n{0} * {1} = {2}", num1,                num2, result);
               break;
           case 4:
               result = (float)num1 / num2;
               Console.WriteLine("\n{0} / {1} = {2}", num1,                num2, result);
               break;
           default:
                   Console.WriteLine("\nInvalid option.                    Please try again.");
                   goto label;
         }
        Console.ReadLine();
      }
   }
}

When the above code is compiled and executed, it produces the following result:

       Menu

Press 1 for add
Press 2 for subtraction
Press 3 for multiplication
Press 4 for Division


Enter first number :       22
Enter second number :   8

Enter your option:          4
22 / 8 = 2.75 

                                                                                                                                           Previous....                                                                                                                                                           Next.....