CS210 - Data Structures and Algorithms 1

INTRODUCTION

Instructor: Dr. Natalie Culligan
Research Areas:
- Behavioral Data
- Education
- Virtual Reality
- Video Games

TEXTBOOKS

Introduction to Algorithms by Cormen, Leiserson, Rivest, and Stein
Data Structures and Algorithms in Java by Goodrich, Tamassia, and Goldwasser

COURSE TOPICS

Object-Oriented Programming (OOP) - revision
Array Algorithms
Algorithm Notation (Big-O, Small-O, Omega, Theta)
Sorting Algorithms
Recursion
Stacks, Queues, Linked Lists

ASSESSMENT

Labs: 10%
Final Exam: 90%

CONTACT INFORMATION

Office: 128, Eolas Building
Office Hours: TBD
Email: Natalie.Culligan@mu.ie

PROGRAMMING LANGUAGE

Java will be used for representing data structures and algorithms
Other popular languages (e.g., C++) can also be utilized

JAVA PROGRAMMING

Java was first released in 1995, developed by James Gosling at Sun Microsystems
Platform independent; runs on any hardware/OS via the Java Virtual Machine (JVM)
Compilation Process:
- Source code (.java file) is converted into bytecode (.class file)

COMPILATION AND EXECUTION

Java programs must be compiled before running, changes necessitate recompilation

VARIABLES & DATA TYPES

Variables: Named storage in memory
- Two types: Primitive (int, double) and Reference (objects)
- Cannot be reserved keywords
- Can be initialized during declaration; undefined if not initialized

SCOPE & GARBAGE COLLECTION

Local variables exist within functions and are destroyed after
Automatic memory management in Java (garbage collection)

ASSIGNMENT

Assignment operator '=' modifies the variable’s value (e.g., total = 55)
Type consistency required when assigning values

PRIMITIVE DATA TYPES

Eight Primitive Types:
- Integers: byte, short, int, long
- Floating Points: float, double
- Character: char
- Boolean: boolean

BITS AND BYTES

1 byte = 8 bits, kilobyte = 1024 bytes, megabyte = 1024^2 bytes

PRIMITIVE TYPE DESCRIPTIONS

Type	Description	Size
int	Integer type, range: -2,147,483,648 to 2,147,483,647	4 bytes
byte	Single byte type, range: -128 to 127	1 byte
short	Short integer type, range: -32,768 to 32,767	2 bytes
long	Long integer type, range: -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807	8 bytes
double	Double-precision floating-point, ~±10308, ~15 decimal digits	8 bytes
float	Single-precision floating-point, ~±103838, ~7 decimal digits	4 bytes
char	Character type (Unicode)	2 bytes
boolean	Boolean values (true/false)	1 bit

NUMBER TYPES

Floats cannot be assigned to integers without casting: use (int)value to convert
Use Math.round to convert floats to nearest integers

ARITHMETIC EXPRESSIONS

Basic arithmetic operators: +, -, *, /, % (modulus)

OPERATOR PRECEDENCE

BOMDAS (Brackets, Orders, Multiplication and Division, Addition and Subtraction)

INCREMENT AND DECREMENT

Increment: ++, Decrement: --
Example: count++ is equivalent to count = count + 1

RELATIONAL OPERATORS

Operator	Description
>	Greater than
>=	Greater than or equal to
<	Less than
<=	Less than or equal to
==	Equal to
!=	Not equal to

COMPARING STRINGS

Use .equals() method for string equality check instead of ==

READING INPUT

Use Scanner class for input
- Syntax Example:
```java
Scanner in = new Scanner(System.in);
int quantity = in.nextInt();

## CONTROL STRUCTURES  
### 1. Sequence  
- Execution of statements in order  

### 2. Selection  
- Use `if`, `if-else`, and `else if` for branching  

### 3. Iteration  
- Use loops: `while`, `do-while`, `for`  

### 4. WRITE YOUR own loops  
- Nested loops and conditional statements possible  

## EXAMPLES  
- **While Loop:**

java
while(condition){
// statements
}

- **For Loop:**

java
for(int i = 0; i < 5; i++) {
// statements
}

- **If-Else Example:**

java
if(condition)
// statement
else
// statement
```

FINAL NOTES

Understand operator precedence
Pay attention to scope, local variables, and object references
Practice coding exercises regularly to strengthen understanding.