c#step17

C# - switch

C# includes another decision making statement called switch. The switch statement executes the code block depending upon the resulted value of an expression.

Syntax:

switch(expression)
{
    case <value1>
        // code block
        break;
    case <value2>
        // code block
        break;
    case <valueN>
        // code block
        break;
    default 
        // code block
        break;
}

As per the syntax above, switch statement contains an expression into brackets. It also includes multiple case labels, where each case represents a particular literal value. The switch cases are seperated by a break keyword which stops the execution of a particular case. Also, the switch can include a default case to execute if no case value satisfies the expression.

 Note:

Case label in switch must be unique. It can be bool, char, string, integer, enum, or corresponding nullable type.

Consider the following example of a simple switch statement.

Example: switch

int x = 10;

switch (x)
{ 
    case 5:
        Console.WriteLine("Value of x is 5");
        break;
    case 10:
        Console.WriteLine("Value of x is 10");
        break;
    case 15:
        Console.WriteLine("Value of x is 15");
        break;
    default:
        Console.WriteLine("Unknown value");
        break;
}

Try it

Output:

Value of x is 10

The switch statement can include expression or variable of any data type such as string, bool, int, enum, char etc.

Example: switch statement

string statementType = "switch";

switch (statementType)
{
    case "if.else":
        Console.WriteLine("if...else statement");
        break;
    case "ternary":
        Console.WriteLine("Ternary operator");
        break;
    case "switch":
        Console.WriteLine("switch statement");
        break;
}

Try it

Output:

switch statement

Goto in switch:

The switch case can use goto to jump over a different case.

Example: goto in switch case

string statementType = "switch";

switch (statementType)
{
    case "DecisionMaking":
        Console.Write(" is a decision making statement.");
        break;
    case "if.else":
        Console.Write("if-else");
        break;
    case "ternary":
        Console.Write("Ternary operator");
        break;
    case "switch":
        Console.Write("switch statement");
        goto case "DecisionMaking";
}

Try it

Output:

switch statement is a decision making statement.

Nested switch:

Nested switch statments are allowed in C# by writing inner switch statement inside a outer switch case.

Example: Nested switch statements

int j = 5;

switch (j)
{
    case 5:
        Console.WriteLine(5);
        switch (j - 1)
        {
            case 4:
            Console.WriteLine(4);
            switch (j - 2)
            {
                case 3:
                Console.WriteLine(3);
                break;
            }
            break;
        }
        break;
    case 10:
        Console.WriteLine(10);
        break;
    case 15:
        Console.WriteLine(15);
        break;
    default:
        Console.WriteLine(100);
        break;
}

Try it

Output:

5 
4
3

 Points to Remember :

1. The switch statement tests the variable against a set of constants.
2. The switch statement contains multiple case labels.
3. The switch case must include 'break' keyword to stop the execution of switch case.
4. The default case executes when no case satisfies the expression.
5. A nested switch statement is allowed.