CS1140 Chapter 2: Elementary Programming

Floating-Point Inaccuracy

Calculations with floating-point numbers can yield inexact results due to representation limits.

Integer Division in Java

Dividing two integers truncates the fractional part, resulting in an integer.

Forcing Floating-Point Division

Make at least one operand a floating-point number (e.g., 2.0 instead of 2).

Redundant Scanner Objects

Creating multiple Scanner instances for System.in is unnecessary and leads to errors.

Redeclaring Variables

No, a variable cannot be redeclared with a different type in the same scope.

Integer Overflow

Occurs when a calculated integer value exceeds its storage type's maximum limit.

Floating-Point Overflow

Yes, floating-point operations can cause overflow, resulting in Infinity.

Runtime Errors from Overflow

No, overflow does not cause a runtime error; it silently wraps around.

Round-Off Error

The difference between the calculated approximation of a number and its exact value.

Integer Round-Off Errors

No, integer operations yield exact results and do not cause round-off errors.

Floating-Point Round-Off Errors

Yes, floating-point operations can cause round-off errors due to binary representation limits.

Algorithm

A step-by-step procedure or formula for solving a problem.

Assignment Operator (=)

Assigns the value on its right to the variable on its left.

Assignment Statement

An executable statement that designates a value for a variable.

byte Type

An 8-bit signed integer primitive data type in Java.

Casting

The process of converting a value from one data type to another.

Constant

An identifier representing permanent data that cannot be changed during execution.

Data Type

A domain of values together with a set of operations on those values.

Declaring Variables

Tells the compiler the variable name and the type of data it holds.

Decrement Operator (--)

Subtracts 1 from a variable.

double Type

A 64-bit double-precision floating-point primitive data type.

Expression

A combination of variables, operators, and values that evaluates to a single value.

final Keyword

A Java modifier used to declare named constants whose values cannot change.

float Type

A 32-bit single-precision floating-point primitive data type.

Floating-Point Number

A number containing a fractional part represented with a decimal point.

Identifier Rules

Must consist of letters, digits, _, or $, and cannot start with a digit.

Increment Operator (++)

Adds 1 to a variable.

Incremental Coding and Testing

Writing and testing code in small, manageable steps to isolate errors easily.

int Type

A 32-bit signed integer primitive data type.

IPO Model

Input, Process, Output — the typical structure of a program execution.

Literal

A constant value appearing directly in a program source code.

long Type

A 64-bit signed integer primitive data type.

Narrowing a Type

Converting a large-range type to a smaller-range type; requires explicit casting.

Operand

A value or variable acted upon by an operator.

Operator

A symbol that performs specific operations on one or more operands.

Postdecrement (var--)

Uses the current value of the variable in the expression, then decrements it.

Predecrement (--var)

Decrements the variable first, then uses its new value in the expression.

Postincrement (var++)

Uses the current value of the variable in the expression, then increments it.

Preincrement (++var)

Increments the variable first, then uses its new value in the expression.

Primitive Data Type

Basic built-in types in Java, such as int, double, float, and byte.

Pseudocode

An informal high-level description of an algorithm using natural language.

Requirements Specification

A formal process that seeks to understand the problem and document requirements.

Scope of a Variable

The part of the program where a variable can be referenced.

short Type

A 16-bit signed integer primitive data type.

Specific Import

Imports a single class explicitly (e.g., import java.util.Scanner;).

Wildcard Import

Imports all classes in a package using an asterisk (e.g., import java.util.*;).

System Analysis

Analyzes data flow and identifies inputs, outputs, and process requirements.

System Design

Designing a system solution, including output formatting, inputs, and algorithmic process.

Underflow

Occurs when a floating-point result is too small to be represented.

UNIX Epoch

Midnight of January 1, 1970 GMT, used as a reference point for time.