if, else, and elseif

An if statement is used to execute an action when a condition is met. The following shows the syntax for an if statement; the statements enclosed by the if statement executes if the condition evaluates to true:

if (<condition>) { 
    <statements> 
} 

The else statement is optional and runs if all previous conditions evaluate to false:

if (<first-condition>) { 
    <first-statements> 
} else { 
    <second-statements> 
} 

The elseif statement allows several conditions to be tested in order:

if (<first-condition>) { 
    <first-statements> 
} elseif (<second-condition>) { 
    <second-statements> 
} elseif (<last-condition>) { 
    <last-statements> 
}

The else statement may be added after any number of elseif statements.

Execution of a block of conditions stops as soon as a single condition evaluates to true. For example, both the first and second condition would evaluate...