# CHAPTER 10: DATA TYPES AND STRUCTURES
## 10.1 DATA TYPES
### 10.1.1 Primitive Data Types
Type
Description
**INTEGER**
Whole numbers
**REAL**
Decimal numbers
**CHAR**
Single character
**STRING**
Sequence of characters
**BOOLEAN**
True/False
**DATE**
Date values
### 10.1.2 Records
**Definition:** A structure that holds a set of data of different types under one identifier.
**Purpose:**
- Group related data of different types
- Like a record in a database
**Example:**
<TEXT>
RECORD Employee
DECLARE EmpID : INTEGER
DECLARE Name : STRING
DECLARE Salary : REAL
END RECORD
## 10.2 ARRAYS
### 10.2.1 One-Dimensional Arrays
**Definition:** A collection of elements of the same type accessed by index.
**Terms:**
- Index: Position of element
- Lower bound: First index (usually 0 or 1)
- Upper bound: Last index
**Declaration:**
<TEXT>
DECLARE arrayname\[upperbound\] : TYPE
**Access:**
<TEXT>
arrayname\[index\]
### 10.2.2 Two-Dimensional Arrays
**Definition:** Array of arrays; elements accessed by row and column.
**Declaration:**
<TEXT>
DECLARE arrayname\[row, column\] : TYPE
### 10.2.3 Array Operations
**Linear Search:**
- Check each element sequentially
- Works on unsorted data
- O(n) time complexity
**Bubble Sort:**
- Compare adjacent elements
- Swap if in wrong order
- Repeat until sorted
- O(n²) time complexity
## 10.3 FILES
### 10.3.1 File Need
- Store data permanently
- Large amounts of data
- Data persistence between program runs
### 10.3.2 File Operations
**Opening:**
<TEXT>
OPENFILE filename FOR READ/WRITE/APPEND
**Reading:**
<TEXT>
READFILE filename, variable
**Writing:**
<TEXT>
WRITEFILE filename, variable
**Closing:**
<TEXT>
CLOSEFILE filename
## 10.4 ABSTRACT DATA TYPES (ADT)
### 10.4.1 Stack
**Characteristics:**
- LIFO (Last In, First Out)
- Add to top (push)
- Remove from top (pop)
**Operations:**
- Push: Add item to top
- Pop: Remove item from top
- Peek: View top item without removing
### 10.4.2 Queue
**Characteristics:**
- FIFO (First In, First Out)
- Add to rear (enqueue)
- Remove from front (dequeue)
### 10.4.3 Linked List
**Characteristics:**
- Dynamic structure
- Nodes contain data and pointer to next node
- Can grow/shrink easily
**Operations:**
- Add node
- Delete node
- Search