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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 keyword on one end and a
break or return statement on the other, with a colon
separating the anticipated value and the statement sequence:
switch (integer-producing expression) {
case integer literal 1: statements for integer 1 break;
case integer literal 2: statements for integer 2 break;
...
default: default statements
}
When such a switch statement is encountered, the integer-producing expression is evaluated,
producing an integer. That value is compared with the integer literals
found following the case keywords. As soon as there is a match,
evaluation of the following statements begins; execution continues up to the first
break or return statement encountered.
The line beginning with the default: keyword is optional. If the
expression produces an integer that fails to match any of the case
integer literals, the statements following the default: keyword are
executed.
If there is no match and no default: keyword, no statements are
executed.