Switch Statement
Switch Statement :
Java has a built in multiway decision making statement known as switch. The switch statement tests the value of a given variable or expression against a list of case values and when a match is found , a block of statements associated with that case is executed.
Program illustration of switch statement
Class cityguide
{
Public static void main( String args[])
{
Char choice;
System.out.println(“Select your choice “);
System.out.println(“M for MAdras “);
System.out.println(“B for Bomday “);
System.out.println(“C for Calcutta “);
System.out.println(“ Choice “);
System.out.flush();
Try
{
Switch( choice = ( char) system.in.read())
{
Case ‘M’:
Case m: system.out.println( “Madras” );
Break;
Case B;
Case b: system.out.println( “ Bombday”);
Break;
Case C:
Case c: system.out.println(“ Calcutta “);
Break;
Default: system.out.println( “ Invalid Choice “);
}
}
Catch ( exception e )
{
System.out.println(“ I / O Error “);
}
}
}
The ? : operator
This operator is a combination of ?and : and takes three operands.This operator is known as the conditional operator.
The general form of the use of the conditional statement is as follows :
Condition1 expression ?expression1 : expression2
The conditional operation is evaluated first. If the result is true expression 1 is evaluated and is returned as the value of conditional expression. Otherwise expression 2 is evaluated and its value is returned.
For example :
If ( x> 0 )
Flag = 0;
Else
Flag = 1;
Can be written as
Flag = (x<0) ?0 : 1
Evaluation of another example :
Y = 1.5x + 3 ; for x <=2
Y = 2x + 3 ; for x > 2
This can be evaluated using conditional operator as follows :
Y = (x – 2) ?( 2 x + 5 ) : ( 1.5x + 3 )