C# 4 and .NET 4

40 ❘ ChaPTer 2 cOre c#
The following code illustrates both how to use goto to simulate fall-through, and how messy the resultant
code can get:
// assume country and language are of type string
switch(country)
{
case "America":
CallAmericanOnlyMethod();
goto case "Britain";
case "France":
language = "French";
break;
case "Britain":
language = "English";
break;
}
There is one exception to the no-fall-through rule, however, in that you can fall through from one case to
the next if that case is empty. This allows you to treat two or more cases in an identical way (without the
need for goto statements):
switch(country)
{
case "au":
case "uk":
case "us":
language = "English";
break;
case "at":
case "de":
language = "German";
break;
}
One intriguing point about the switch statement in C# is that the order of the cases doesn’t matter — you
can even put the default case first! As a result, no two cases can be the same. This includes different
constants that have the same value, so you can’t, for example, do this:
// assume country is of type string
const string england = "uk";
const string britain = "uk";
switch(country)
{
case england:
case britain: // This will cause a compilation error.
language = "English";
break;
}
The previous code also shows another way in which the switch statement is different in C# compared to
C++: In C#, you are allowed to use a string as the variable being tested.
loops
C# provides four different loops (for, while, do . . . while, and foreach) that allow you to execute a block
of code repeatedly until a certain condition is met.
The for loop
C# for loops provide a mechanism for iterating through a loop where you test whether a particular
condition holds before you perform another iteration. The syntax is:
for (initializer; condition; iterator)
statement(s)
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