Understanding selection statements

Every application needs to be able to select from choices and branch along different code paths. The two selection statements in C# are if and switch. You can use if for all your code, but switch can simplify your code in some common scenarios, such as when there is a single variable that can have multiple values that each require different processing.

Branching with the if statement

The if statement determines which branch to follow by evaluating a Boolean expression. If the expression is true, then the block executes. The else block is optional, and it executes if the if expression is false. The if statement can be nested.

The if statement can be combined with other if statements as else if branches, as shown in the following code:

if (expression1)
{
  // Executes if expression1 is true.
}
else if (expression2)
{
  // Executes if expression1 is false and expression2 is true.
}
else if (expression3)
{
  // Executes if expression1...