A switch statement permits variable to be tested for equality against an inventory of values. Every value is understood as a case, and also the variable being switched on checked for every case.
The java switch expression are often accepted in expression kind as a computer memory unit, short, int primitive information sorts, enums and also the string category. not like if- then and if - then - else statements, the switch statement contains a variety of attainable execution ways.
The traditional method of exploitation Switch Statement supports fallthrough which might introduce bugs just in case the programmer forgets to feature associate degree applicable break statement.
Semantics, there are two main forms of switch statements.
The first form are structured switches as in Pascal, where exactly one branch is taken, and the cases are treated as separate, exclusive blocks, this function as a generalized if then else conditional , here with any number of branches, not just two.
The second form is instructured switches, as in C, where the cases are treated as labels within a single block and the switch function as generalized go to. The distinction is referred to as the treatment of fall through
Fall through
In many languages, only the matching block is executed, and then execution continues at the end of the switch statement. These include the Pascal family as well as PL/I, modern forms of Fortran and BASIC dialects influenced by Pascal , most functional languages and many others.
Compilation
A branch table allows the switch statement java to determine with a small, constant number of instructions which branch to execute without having to go through list of comparison, while a binary search takes only logarithmic number of comparisons, measured in the number of case in the switch statement.
Normally the only method of finding out if this optimization has occurred is by actually looking at the resultant assembly or machine code output that has been generated by the complier.
The syntax of the Switch Case Statement is as mentioned below.
// Switch Statement
switch( Conditional Expression ) {

// Case Statement having value type same as that of the Expression
case option1:

// Case Statements

break;

case option2:

// Case Statements

break;

default:

// Default Statements
}

// OR - More readable with clear separation of case statements
switch( Expression ) {

// Case Statement having value type same as that of the Expression
case option1: {

// Case Statements

break;
}
case option2: {

// Case Statements

break;
}
default: {

// Default Statements
}
}

1. Duplicate case values are not allowed.

2. The value for a case must be of the same data type as the variable in the switch.
3. The case must be have constant and literal value.
4. There can be one or N number of cases values for a switch expression.
5. When a break statement is reached, the switch terminates, and the flow of control jumps to the next line following the switch statement.
6. Not an every case of switch statement needs to take a break. If no break appears, the flow of control will fall through the subsequent cases until a break is reached.
7. A switch statement has an optional default case, which must appear at the end of the switch. The default case can be used in performing a task when none of the case is true . No break is required in default case.