`switch` statements

BASIC

Just as the if statement provides a choice between two blocks of code, based on a boolean value, the switch statement provides a choice between several blocks of code, based on an integer value.

The syntax is fairly complex:

switch (integer_expression) {
    case integer_constant_1:
        statements;
        break;
    case integer_constant_2:
        statements;
        break;
    ...
    case integer_constant_N:
        statements;
        break;
    default:
        statements;
        break;
}

where:

The integer_expression must evaluate to one of the following types: int, byte, short, long, char (Java 5 also allows Integer, Byte, Short, Long, Character, and Enum).
The integer_constant_x values must be either literal values (such as 5) or constants declared with the keyword final.
The statements may be any sequence of zero or more statements. Notice that it is not necessary to use braces to form the statements (along with the following break statement) into a block, although this is sometimes done.
The break statement is not required at the end of each case; however, if it is omitted, control will flow into the next set of statements. This is seldom what you want to happen. On the rare occasion that this is the desired behavior, you should include a comment that the omission of break is intentional, otherwise you may "correct" this problem at some later date.
The default case should come last. It is good style to always include a default case, even if you believe that all possibilities have been covered; in this case, you can put the statement assert false; in the default case to document your belief.
The break statement in the last case is unnecessary. I think it's good style to put a break in every case, but this opinion is controversial.

Operation is as follows. The integer_expression is evaluated, then compared against each case in order. When a matching integer_constant is found, execution begins at the following statements, and continues until either a break (or a return) is encountered, or until the end of the switch statement.

switch statements

`switch` statements