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The C Users' Group Library 1994 August
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wc-cdrom-cusersgrouplibrary-1994-08.iso
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vol_300
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310_01
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bag.st
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1990-04-20
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Class Bag :Collection
| dict count |
[
new
dict <- Dictionary new
| add: newElement
dict at: newElement
put: (1 + (dict at: newElement ifAbsent: [0]))
| add: newObj withOccurrences: anInteger
anInteger timesRepeat: [ self add: newObj ].
^ newObj
| remove: oldElement ifAbsent: exceptionBlock | i |
i <- dict at: oldElement
ifAbsent: [ ^ exceptionBlock value].
(1 = i) ifTrue: [dict removeKey: oldElement]
ifFalse: [dict at: oldElement put: i - 1 ]
| size
^ dict inject: 0 into: [:x :y | x + y]
| occurrencesOf: anElement
^ dict at: anElement ifAbsent: [0]
| first
(count <- dict first) isNil ifTrue: [^ nil].
count <- count - 1.
^ dict currentKey
| next
[count notNil] whileTrue:
[ (count > 0)
ifTrue: [count <- count - 1. ^ dict currentKey]
ifFalse: [(count <- dict next) isNil
ifTrue: [^ nil] ]].
^ nil
]