Chapter 2 Flashcards
Briefly explain what is meant by the syntax and the semantics of a programming language. Give an example to illustrate the difference between a syntax error and a semantics error.
What does the computer do when it executes a variable declaration statement. Give an example.
What is a type, as this term relates to programming?
One of the primitive types in Java is boolean. What is the boolean type? Where are boolean values used? What are its possible values?
Give the meaning of each of the following Java operators:
a) ++
b) &&
c) !=
Explain what is meant by an assignment statement, and give an example. What are assignment statements used for?
What is meant by precedence of operators?
What is a literal?
In Java, classes have two fundamentally different purposes. What are they?
What is the difference between the statement “x = TextIO.getDouble();” and the statement “x = TextIO.getlnDouble();”
Explain why the value of the expression 2 + 3 + “test” is the string “5test” while the value of the expression “test” + 2 + 3 is the string “test23”. What is the value of “test” + 2 * 3 ?
Integrated Development Environments such as Eclipse often use syntax coloring, which assigns various colors to the characters in a program to reflect the syntax of the language. A student notices that Eclipse colors the word String differently from int, double, and boolean. The student asks why String should be a different color, since all these words are names of types. What’s the answer to the student’s question?
What is the purpose of an import directive, such as import textio.TextIO or import java.util.Scanner?
Write a complete program that asks the user to enter the number of “widgets” they want to buy and the cost per widget. The program should then output the total cost for all the widgets. Use System.out.printf to print the cost, with two digits after the decimal point. You do not need to include any comments in the program.
