C# 5.0 Programmer's Reference

Decision Statements ❘ 153
If it’s not Monday and it is Friday, the program sets greeting to "Finally, it's Friday!"
If it’s neither Monday nor Friday, the program sets greeting to "Welcome to" followed by the
current day of the week.
After the series of if-else statements, the program displays the greeting in a message box.
The final else section is optional. If you don’t include it and none of the conditions are true, the
program doesn’t execute any of the corresponding statements.
All the else if statements are also optional. If the code includes only an if statement, either the
program executes the statement that follows or it doesn’t, depending on the value of the condition.
For example, the following code uses a single if statement to display a message box only if it’s
Monday. If it’s any other day of the week, the program does nothing.
if (DateTime.Now.DayOfWeek == DayOfWeek.Monday)
MessageBox.Show("Sorry, it's Monday.");
The “statement” that the program executes when a condition is true can actually be a block of
statements surrounded by braces. The following shows the syntax.
if (condition1)
{
statement1;
}
else if (condition2)
{
statement2;
}
else if (condition3)
{
statement3;
}
...
else
{
statementElse;
}
You can place as many statements as you like between the braces.
switch Statements
The switch statement lets a program execute one of several pieces of code depending on a single
value. The result is similar to a series of if-else statements that compare a single value to a series
of other values.
The basic syntax is as follows:
switch (value)
{
case expression1:
statements1;
break;
case expression2:
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