Page 76 - DCAP201_FUNDAMENTALS_OF_DATA_STRUCTURES

Unit 5: Pointers

items Month, Day and Year, and Father and Mother are group items, each with sub items Name Notes
and Age.
Let we describe the structure of the above record. (Name appears three times and age appears
twice in the structure.)
1 Newborn
2 Name

2 Sex
2 Birthday
3 Month
3 Day

3 Year
2 Father
3 Name
3 Age

2 Mother
3 Name
3 Age
The number to the left of each identifier is called a level number. Observe that each group item
is followed by its sub items, and the level of the sub items is 1 more than the level of the group
item. Furthermore, an item is a group if and only if it is immediately followed by an item with
a greater level number.
Some of the identifiers in a record structure may also refer to arrays of elements. In fact, the first
line of the above structure is replaced by
1 Newborn(20)
This will indicate a file of 20 records, and the usual subscript notation will be used to distinguish
between different records in the file. That is, we will write to
Newborn1, Newborn2, Newborn3, . . .
or
Newborn[1], Newborn[2], Newborn[3],. . .

to denote different records in the file.

Example:
A class of student records may be organized as follows:
1 Student(20)
2 Name
3 Last

3 First
3 MI (Middle Initial)

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