Mathematical Functions, Characters, and Strings

This flashcard set covers the essentials of Java's Math class, character handling, String object methods, and output formatting as presented in CSC110 AB.

$$\text{Sequence}$$

A control structure where statements execute one after another from top to bottom.

$$\text{Selection}$$

A control structure where a decision is made based on a boolean condition.

$$==$$

The comparison operator used to check for equality in a condition.

$$=$$

The assignment operator used to set the value of a variable.

$$\text{Fall-through}$$

A situation in a switch statement where forgetting a break causes all cases below the match to execute.

$$\&\&$$

The AND boolean operator which is true only if both conditions are true.

$$||$$

The OR boolean operator which is true if at least one condition is true.

$$!$$

The NOT boolean operator which flips the boolean value.

$$\text{Math Class}$$

A built-in Java toolkit that provides static methods for common mathematical operations and requires no import.

$$\text{Math.abs(x)}$$

Returns the absolute value or distance from zero for the provided number.

$$\text{Math.pow(base, exponent)}$$

Returns the value of the base raised to the power of the exponent as a double.

$$\text{Math.sqrt(x)}$$

Returns the square root of the specified value.

$$\text{Math.ceil(x)}$$

Rounds a decimal number UP to the nearest whole number.

$$\text{Math.floor(x)}$$

Rounds a decimal number DOWN to the nearest whole number.

$$\text{Math.round(x)}$$

Rounds a number to the nearest whole number integer.

$$\text{Math.random()}$$

Returns a pseudo-random double value in the range [0.0, 1.0).

$$\text{Random Integer Formula}$$

The expression $\text{(int)(Math.random() * range) + min}$ where range is $\text{max - min + 1}$; used to generate integers within a specific inclusive range.

$$\text{Pseudo-random Numbers}$$

Numbers generated by deterministic algorithms that are predictable if the starting seed is known.

$$\text{Seed}$$

An initial value that determines the entire sequence of numbers generated by a random number generator.

$$\text{Math.PI}$$

A built-in constant representing the ratio of a circle's circumference to its diameter, approximately $3.141592653589793$.

$$\text{char}$$

A primitive type that stores a single character wrapped in single quotes, such as $\text{'A'}$.

$$\text{Unicode}$$

A universal encodings system used by Java that assigns a unique number to every character in every language.

$$\text{ASCII}$$

The first 128 characters of the Unicode set, including standard English letters and numbers.

\text{\n}

The escape sequence for a new line.

\text{\t}

The escape sequence for a horizontal tab.

\text{\"}

The escape sequence for a double quote.

\text{\}

The escape sequence for a backslash.

$$\text{Character.isDigit(c)}$$

A static method that returns true if the specified character is a digit.

$$\text{Character.isLetter(c)}$$

A static method that returns true if the specified character is a letter.

$$\text{Object}$$

A variable that has both data (information) and behaviors (methods), stored as a reference to a memory address.

$$\text{String}$$

An object type in Java that stores a sequence of characters wrapped in double quotes.

$$\text{length()}$$

A String method that returns the number of characters in the string, including spaces and punctuation.

$$\text{charAt(i)}$$

A String method that returns the character at the specific index $i$, where the first character is at index $0$.

$$\text{Concatenation}$$

The process of joining strings together using the $+$ operator.

$$\text{trim()}$$

A String method that removes leading and trailing spaces from a string.

$$\text{next()}$$

A Scanner method that reads one word and stops at a space or Enter key.

$$\text{nextLine()}$$

A Scanner method that reads the entire line, including spaces, and stops only at the Enter key.

$$\text{equals()}$$

The method used to compare the content of two strings for an exact, case-sensitive match.

$$\text{compareTo()}$$

A method that returns $0$ if strings are equal, a negative value if the string comes before another alphabetically, or a positive value if it comes after.

$$\text{substring(start, end)}$$

Extracts a portion of a string from the start index up to, but not including, the end index.

$$\text{indexOf()}$$

Searches for a character or substring and returns its position, or $-1$ if not found.

$$\text{printf}$$

A method used for formatted output, providing precise control over alignment, decimal places, and columns.

$$\%d$$

A printf format specifier used for integers.

$$\%s$$

A printf format specifier used for strings.

$$\%.2f$$

A printf format specifier used to display a decimal number with two decimal places.

$$\text{Text Block}$$

A multi-line string starting and ending with triple quotes $(""")$, introduced in Java 15+ to preserve formatting without escape sequences.