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The purpose of a
switch statement is to execute a
particular sequence of statements according to the value of an
expression that produces an integer. In most switch
statements, each anticipated value of the integer-producing
expression and the corresponding sequence of statements is
sandwiched between a case symbol on one end and a
break
statement on the other, with a colon separating the anticipated
value and the statement sequence:
switch (integer-producing expression) {
case integer constant 1: statements for integer 1 break;
case integer constant 2: statements for integer 2 break;
...
default: default statements
}
When such a switch statement is encountered, the expression is evaluated,
producing an integer. That value is compared with the integer constants
found following the case symbols. As soon as there is a match,
evaluation of the following statements begins; it continues up to the first
break statement encountered.
The line beginning with the default symbol is optional. If the
expression produces an integer that fails to match any of the case
integer constants, the statements following the default symbol are
executed.
If there is no match and no default symbol, no statements
are executed.