Decision Making Statements and Loops

If..Else :

• Executes code if the conditional is true. If the conditional is not true, code specified in the else clause is executed.

Syntax:

if conditional [then]

 code...

[elsif conditional [then]

 code...]

[else

 code...]

end

Example:

If Modifier:

• Executes code if the conditional is true.

Syntax: 
code if condition

Example:

Unless Statement:

• Executes code if conditional is false. If the conditional is true, code specified in the else clause is executed.

Syntax:

unless conditional [then]

   code

[else

   code ]

end

Example:

Unless Modifier:

• Executes code if conditional is false.

Syntax:

code unless conditional

Example:

Case Statement:

• Compares the expression specified by case and that specified by when using the === operator and executes the code of the when clause that matches.

Syntax:

case expression

[when expression [, expression ...] [then]

   code ]...

[else

   code ]

end

Example:

Ruby Loops:

While Statement:

• Executes code while conditional is true. A while loop's conditional is separated from code by the reserved word do, a newline, backslash \, or a semicolon ;.

Syntax:

while conditional [do]

   code

end

Example:

While Modifier:

• Executes code while conditional is true.

Syntax:

code while condition

OR

begin 

  code 

end while conditional

Example:

Until Statement:

• Executes code while conditional is false. An until statement's conditional is separated from code by the reserved word do, a newline, or a semicolon.

Syntax:

until conditional [do]

   code

end

Example:

Until Modifier:

• Executes code while conditional is false.

Syntax:

code until conditional

OR

begin

   code

end until conditional

Example:

For Statement:

• Executes code once for each element in expression.

Syntax:

for variable [, variable ...] in expression [do]

   code

end

Example: