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Understanding switch statement syntax
The syntax of a switch statement is as follows (switch, case, and default are keywords):
switch ( controllingExpression )
{
case constantExpression :
statements
break;
case constantExpression :
statements
break;
...
default :
statements
break;
}
The controllingExpression, which must be enclosed in parentheses, is evaluated once. Control then
jumps to the block of code identified by the constantExpression whose value is equal to the result
of the controllingExpression. (The constantExpression identifier is also called a case label.) Execution
runs as far as the break statement, at which point the switch statement finishes and the program
continues at the first statement that follows the closing brace of the switch statement. If none of the
constantExpression values is equal to the value of the controllingExpression, the statements below the
optional default label run.
Note Each constantExpression value must be unique so that the controllingExpression
will match only one of them. If the value of the controllingExpression does not match any
constantExpression value and there is no default label, program execution continues with
the first statement that follows the closing brace of the switch statement.
So, you can rewrite the previous cascading if statement as the following switch statement:
switch (day)
{
case 0 :
dayName = "Sunday";
break;
case 1 :
dayName = "Monday";
break;
case 2 :
dayName = "Tuesday";
break;
...
default :
dayName = "Unknown";
break;
}
100 PART I Introducing Microsoft Visual C# and Microsoft Visual Studio 2015