Repetition

A quantifier is used to repeat an element; three of the quantifiers have already been introduced: *, +, and ?. The quantifiers are as follows:

Description	Character	Example
The preceding character repeated zero or more times	*	'abc'-match 'a*' 'abc'-match '.*'
The preceding character repeated one or more times	+	'abc'-match 'a+' 'abc'-match '.+'
Optional character	?	'abc' -match 'ab?c' 'ac' -match 'ab?c'
A fixed number of characters	{exactly}	'abbbc' -match 'ab{3}c'
A number of characters within a range	{min,max}	'abc' -match 'ab{1,3}c' 'abbc' -match 'ab{1,3}c' 'abbbc' -match 'ab{1,3}c'
No less than a number of characters	{min,}	'abbc' -match 'ab{2,}c' 'abbbbbc' -match 'ab{2,}c'

Each *, +, and ? can be described using a curly brace notation:

• * is the same as {0,}
• + is the same as {1,}
• ? is the same as {0,1}

It is extremely uncommon to find examples where the functionality of special characters is replaced with curly braces. It is equally uncommon to find examples where the quantifier {1} is used as it adds unnecessary...