9.13. Swift if…else if…else statement

One if statement can be followed by an optional else if...else statement else if...else statement is useful when testing multiple conditional statements.

When using statements such as if , else if , and else , you need to pay attention to the following points:

if there can be 0 or 1 after the statement else . But if there is else if statement else statement needs to be specified in the else if statement.
if statement can be followed by 0 or more else if statement elseif statement must be in the else before the statement appears.
Once if statement executed successfully, others else if or else statements are not executed.

9.13.1. Grammar #

if boolean_expression_1 { /* If boolean_ Expression_1 expression is true, execute the statement */ } else if boolean_expression_2 { /* If boolean_ Expression_2 expression is true, execute the statement */ } else if boolean_expression_3 { /* If boolean_ Expression_3 expression is true, execute the statement */ } else { /* If none of the above conditional expressions are true, execute the statement */ } 

9.13.2. Example #

import Cocoa var varA:Int = 100; /*Detect Boolean conditions*/ If varA==20{ /*If the condition is true, execute the following statement*/ Print ("The value of varA is 20"); }Else if varA==50{ /*If the condition is true, execute the following statement*/ Print ("The value of varA is 50"); }Else{ /*If all the above conditions are false, execute the following statement*/ Print ("no matching criteria"); } Print ("The value of the varA variable is (varA)"); 

When the above code is compiled and executed, it produces the following results:

No matching criteria The value of the varA variable is 100 