C# - Switch Statement

Advertisements


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 through to 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. No break is needed in the default case.

Flow Diagram:

switch statement in C#

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 done
Your grade is B


Advertisements
Advertisements