First Programs Flashcards
What must a computer be able to do to perform useful tasks?
Communicate with the outside world.
What is the term for displaying information for users to read?
Output.
What is the first step in creating a program?
Convert instructions to pseudocode.
What is the simple algorithm to print ‘The answer is 42’?
System.out.println(“The answer is 42”); or System.out.print(“The answer is 42”);
What does the following Java program do?
public class Message1 {
public static void main(String[] args) {
System.out.println(‘The answer is 42’);
}
}
Prints ‘The answer is 42’ to the screen.
What are comments in a program used for?
Help people understand the program.
What are the two styles of comments in Java?
Single line comment: // comment
Multi line comment: /* comment */
What is the structure for defining a class in Java?
public class <CLASSNAME { <CONTENTS>
}</CONTENTS>
What must the name of the file containing a Java program match?
The name of the class.
What method must every Java program contain?
One method called main.
What does the body of a method contain?
The instructions.
What signifies the end of a statement in Java?
A semicolon.
What is System.out in Java?
The standard output object.
What does the method System.out.print do?
Displays a line of text without moving to a new line.
What is the output of this code?
public class Wakey1 { public static void main(String[] args) {
System.out.print(‘Wake up’);
System.out.println(‘ at the back!’);
}
}
Wake up at the back!
What is the special character used to print a new line in Java?
‘\n’.
What is important for program layout?
Blank lines and indentation.
How do you call a method in Java?
By using its name followed by parentheses () and a semicolon.
What is a fundamental advantage of using methods in programming?
Reuse and simplify code.
What does the following method do?
public static void triangle() {
System.out.println(‘ + ‘);
System.out.println(‘ + + ‘);
System.out.println(‘+—+’);
}
+
++
+—+
What does the lamp method do in the following code?
public static void lamp() {
square();
triangle();
}
Draws a square followed by a triangle.
What does the main method do in a Java program?
It is where the program starts execution.
