Java Data Types

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Questions and Answers

What is the default data type of a floating point literal in Java?

double

What is the purpose of appending 'f' or 'F' to a floating point literal in Java?

To specify a 32-bit value

What is the character set used by the Java Programming language?

Unicode

How are character literals represented in Java?

Enclosed by single quotes Signup and view all the answers

What is the purpose of escape sequences in character literals in Java?

To represent special characters Signup and view all the answers

How are string literals represented in Java?

Enclosed by double quotes Signup and view all the answers

What is thrown by the parse method when it is given a string that cannot be converted into a number?

NumberFormatException Signup and view all the answers

What is the advantage of using nextInt() and nextDouble() methods?

They automatically perform the necessary parsing Signup and view all the answers

Why should you use Integer.parseInt(scan.nextLine()) instead of scan.nextInt()?

To accept inputs as strings Signup and view all the answers

What is the method to parse a string into a long?

parseLong() Signup and view all the answers

What is the method to parse a string into a float?

parseFloat() Signup and view all the answers

What happens when you try to convert a string that cannot be converted into a number using the next methods?

An Exception is thrown Signup and view all the answers

What is the purpose of the %+ character in the format %+8d?

To include the + character in the output string Signup and view all the answers

What does the %n format specifier represent in a string format specification?

A newline character Signup and view all the answers

What type of value does the %f format specifier correspond to?

A floating point number Signup and view all the answers

What is the effect of the 8 in the format %+8d?

It right-justifies the number on an 8-space area Signup and view all the answers

What type of value does the %d format specifier correspond to?

An integral number Signup and view all the answers

What is the format specification for displaying a whole number with a comma to group 3 digits in the usual practice for writing big numbers?

%+,8d Signup and view all the answers

What is the purpose of the minus sign in the format specification '-%10.3f'?

To cause left-justification Signup and view all the answers

What is the format specification for displaying a floating point number with a decimal point and 3 digits after the decimal point?

%10.3f Signup and view all the answers

What is the purpose of the '+' sign in the format specification '%+,8d'?

To display a plus sign Signup and view all the answers

What is the format specification for displaying a whole number in an 8-space area with leading zeros?

%08d Signup and view all the answers

What is the result of the expression 'principal * rate'?

A floating point number Signup and view all the answers

What is the purpose of using parentheses in Java expressions?

To make the code more readable and avoid ambiguity Signup and view all the answers

What is the correct order of operations in the expression 20/5*2?

First divide 20 by 5, then multiply the result by 2 Signup and view all the answers

What is the purpose of theCoding Guideline mentioned in the text?

To make the code more readable and easier to understand Signup and view all the answers

What is the purpose of rewriting the expression 6%2*5+4/2+88-10?

To make the expression more readable by adding parentheses Signup and view all the answers

Which of the following expressions is equivalent to the original expression 6%2*5+4/2+88-10?

((6%2)*5)+(4/2)+88-10 Signup and view all the answers

What is the rule followed by the operators / and * in the expression 20/5*2?

Associative rule Signup and view all the answers

Study Notes

Formatting Output

System.out.printf() method is used to format output.
%+8d is used to display a whole number, right-justified, in an 8-space area, with a + character and commas to group 3 digits.
%10.3f is used to display a floating-point number, right-justified, in a 10-space area, with a decimal point and 3 digits after the decimal point.
- character is used for left-justification.

Operator and Operand

principal * rate is an expression that uses the multiplication operator.
Floating-point literals can be expressed in standard notation (e.g., 0.005) or scientific notation (e.g., 5e-3).
To use a smaller precision (32-bit) float, append the "f" or "F" character.

Boolean Literals

A Boolean literal is either true or false.
Example: while (true) { ... }

Character Literals

Unicode characters are used by Java.
A Unicode character is a member of a 16-bit character set.
Character literals represent single Unicode characters, enclosed in single quote delimiters.
Escape sequences are used for special characters (e.g., \n for newline, \t for tab space).

String Literals

String literals represent a sequence of characters, enclosed in double quotes.
Example: rate = Double.parseDouble(scanner.nextLine());

Using the Scanner Class

nextInt(), nextDouble(), and other methods automatically perform parsing.
An Exception is thrown if a string cannot be converted into a number.
Integer.parseInt() and Double.parseDouble() methods are used to parse strings to numbers.

Formatting Output using Placeholders

%d is used for an integral number, %f for a floating-point number, %s for a string, %c for a character, %n for the newline character, and %t for the tab space.
The + character in the format string specifies that the number should be displayed with a + sign.

Tips and Guidelines

Use Integer.parseInt(scan.nextLine()) instead of scan.nextInt() to ensure that a string input is accepted.
Keep expressions simple and use parentheses whenever possible to ensure readability.

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