TM

COMP SCI MIDTERM

Here are definitions of the terms as they relate to Java:

Chapter 1:

Hardware, Program, and Software

  • Hardware: The physical components of a computer, such as the CPU, memory, and storage.

  • Program: A set of instructions that a computer follows to perform a task.

  • Software: The collection of programs that control hardware and execute tasks.

Programming Language, JAVA Programming Language

  • Programming Language: A formal set of instructions that a computer can execute.

  • JAVA Programming Language: A high-level, object-oriented language that is platform-independent due to the Java Virtual Machine (JVM).

Identifiers, Legal Identifiers

  • Identifiers: Names used for variables, methods, classes, etc.

  • Legal Identifiers: Must start with a letter, underscore, or dollar sign and cannot be a Java keyword.

White Space

  • Spaces, tabs, and newlines that improve readability but do not affect execution.

Program Development

  • The process of designing, writing, testing, and maintaining a program.

Language Levels

  • Levels of programming abstraction: Machine language, Assembly, High-level language (e.g., Java).

Compilation

  • Converting Java source code into bytecode using the Java compiler.

Java Translation

  • The process where Java source code is compiled into bytecode and then interpreted by the JVM.

Development Environments

  • Tools used for Java programming (e.g., Eclipse, IntelliJ, NetBeans).

Syntax and Semantics

  • Syntax: The rules governing the structure of valid Java code.

  • Semantics: The meaning of Java statements.

Three Types of Errors

  1. Syntax Errors: Violations of Java's rules (e.g., missing semicolons).

  2. Runtime Errors: Errors occurring during execution (e.g., division by zero).

  3. Logical Errors: Incorrect logic leading to undesired output.

Problem Solving

  • The process of designing a solution and implementing it in code.

Development Activities

  • Steps in creating a program: analysis, design, coding, testing, debugging.

Object-Oriented Programming (OOP)

  • A programming paradigm based on objects and classes.

Objects

  • Instances of a class containing attributes (fields) and behaviors (methods).

Classes

  • Blueprints for creating objects.

Classes and Objects

  • Classes define object properties; objects are instances of classes.

Chapter 2:

Character Strings

  • Sequences of characters handled by the String class.

Two Ways to Create String Objects

  1. Using string literals: String s = "Hello";

  2. Using new: String s = new String("Hello");

Println/print Method

  • System.out.print(): Prints without a newline.

  • System.out.println(): Prints with a newline.

String Concatenation

  • Combining strings using +: "Hello" + " World" results in "Hello World".

Escape Sequences

  • Special characters (\n, \t, \\, etc.).

Variables

  • Named storage locations in memory.

Assignment

  • Assigning values using =.

Constants

  • Immutable values declared with final.

Primitive Data Types

  • byte, short, int, long, float, double, char, boolean.

Numeric Types

  • Integer (int, long) and floating-point (float, double).

Characters

  • Represented using char, e.g., char c = 'A';.

Booleans

  • true or false values.

Expressions

  • Combinations of variables, operators, and values.

Division and Remainder

  • / for division, % for remainder.

Assignment Revisited

  • Assigning values with operators (+=, -=, etc.).

Increment and Decrement Operators

  • ++ and -- increase or decrease a variable by 1.

Assignment Operators

  • =, +=, -=, *=, /=, %=.

Data Conversions

  1. Assignment Conversion: Implicit conversion in assignments.

  2. Promotion: Widening conversion (e.g., int to double).

  3. Casting: Explicit conversion using (type).

Scanner Class

  • Used for input reading (Scanner sc = new Scanner(System.in);).

Reading Input

  • Methods like nextInt(), nextDouble(), nextLine().

Input Tokens

  • Individual units of input parsed by Scanner.

Chapter 3:

Creating Objects

  • ClassName obj = new ClassName();

Creating Strings (Two Ways)

  1. Using literals.

  2. Using new.

Invoking Methods

  • Calling methods on objects: obj.method();.

Object References

  • Variables storing memory addresses of objects.

Assignment Revisited

  • Assigning references, not copying objects.

Aliases

  • Multiple references to the same object.

String Class and Methods

  • Methods like length(), substring(), toUpperCase().

Java API/Packages

  • Predefined Java libraries.

Import Declarations

  • import java.util.Scanner;.

The java.lang Package

  • Implicitly imported (contains Math, String, etc.).

Random Class

  • Generates random numbers (Random rand = new Random();).

Wrapper Classes

  • Convert primitives to objects (Integer, Double, etc.).

Autoboxing

  • Automatic conversion between primitives and wrapper objects.

Chapter 7:

Definition of Array

  • A collection of elements of the same type.

Declaring Arrays

  • int[] arr;.

Using Arrays

  • Access elements with indices.

Bounds Checking

  • Java prevents accessing indices out of range.

Alternate Array Syntax

  • int arr[];.

Initializer Lists

  • int[] arr = {1, 2, 3};.

Two-Dimensional Arrays

  • int[][] matrix = new int[3][3];.

Pros and Cons of Arrays

  • Pros: Fast access, easy iteration.

  • Cons: Fixed size, memory overhead.

Chapter 8:

Concepts of Inheritance

  • A subclass inherits attributes and methods from a superclass.

Examples of Parent/Child Classes

  • Words: Noun extends Word.

  • Book: Ebook extends Book.

  • Hospital Employee: Doctor extends Employee.

The protected Modifier

  • Allows subclass access but prevents outside access.

The super Reference

  • Calls superclass constructor/methods.

Overloading vs. Overriding

  • Overloading: Same method name, different parameters.

  • Overriding: Redefining superclass methods in a subclass.

Class Hierarchies

  • Organized structure of classes.

The Object Class

  • The root of all Java classes.

Abstract Classes

  • Cannot be instantiated; contains abstract methods.

Visibility Revisited

  • public, private, protected.

Designing for Inheritance

  • Using super and protected members.

Chapter 9:

Binding

  • The association of a method call with its definition.

What is Polymorphism?

  • The ability of a method to take different forms.

References and Inheritance

  • A superclass reference can hold a subclass object.

Polymorphism via Inheritance

  • Subclasses can override superclass methods and be referenced polymorphically.

Let me know if you need further clarification on any term!