CS 4A: Chapter 2 – Elementary Programming – Flashcards
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Are these declarations correct? True/False int length, width; int length; int width;
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True
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Are these declarations legal? True/False int t=4.5; int t=(int)false;
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False
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How would you declare Pi as a constant?
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final double PI 3.14159;
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What is the correct way to assign character 5 to c?
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char c = '5';
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parseInt is a method in what class?
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Integer
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Are these incorrect? True/False i == j == k == 1; i = 1 = j = 1 = k = 1;
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True
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Can you cast a character value to an int, or an int to char? True/False
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True
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What is the Java assignment operator ?
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=
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Note that the Unicode for character A is 65. The expression 'A' + 1 evaluates to ________.
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66
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Can you change the value of a constant? True/False
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False
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What do you write to declare a constant MAX_LENGTH inside a method with value 99.98?
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final double MAX_LENGTH = 99.98;
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How would you print: smithexam1test.txt?
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System.out.println("smithexam1test.txt");
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The following code fragment reads in two numbers: Scanner scanner = new Scanner(System.in); int i = scanner.nextInt(); double d = scanner.nextDouble(); What are the correct ways to enter these two numbers?
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- Enter an integer, a space, a double value, and then the Enter key. - Enter an integer, an Enter key, a double value, and then the Enter key. - Enter an integer, two spaces, a double value, and then the Enter key.
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If a program compiles fine, but it produces incorrect result, then the program suffers ________.
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A logic error
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________ are valid Java identifiers.
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- $Java - _RE4
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Are these valid identifiers? True/False $343 radius
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True
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The ________ method returns a raised to the power of b.
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Math.pow(a, b)
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You can cast a double value to ________.
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- short - byte - int - float - long
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To assign a double variable d to a float variable x, you write:
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x = (float)d;
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Any assignment statement can be used as an assignment expression. True/False
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True
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A variable may be assigned a value only once in the program. True/False
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False
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Suppose i is an int type variable. Which of the following statements display the character whose Unicode is stored in variable i?
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System.out.println((char)i);
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Is 'a' larger than 'A'?
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Yes
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The expression (int)(76.0252175 * 100) / 100 evaluates to ________.
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76
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A Java character is stored in ________.
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Two bytes
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The ________ method displays an input dialog for reading a string.
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- String string = JOptionPane.showInputDialog(null, "Enter a string", "Input Demo", JOptionPane.QUESTION_MESSAGE); - String string = JOptionPane.showInputDialog(null, "Enter a string"); - String string = JOptionPane.showInputDialog("Enter a string");
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-24 % -5 is ________.
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-4
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You can always assign a value of int type to a variable of long type without loss of information. True/False
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True
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Which of the following operators has the highest precedence? /, *, +, Casting
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Casting
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To add number to sum, you write:
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- sum += number; - sum = sum + number;
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Note that the Unicode for character A is 65. The expression "A" + 1 evaluates to ________.
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A1
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To assign a double variable d to an int variable x, you write:
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x = (int)d;
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currentTimeMills is a method in the ________ class.
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System
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-15 % 4 is ________.
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-3
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parseDouble is a method in the ________ class.
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Double
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What is the printout of System.out.println('z' - 'a')?
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25
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What is the correct expression of character 4?
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'4'
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Pow is a method is what class?
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Math
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What is the value of (double) 5/2?
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2.5
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The System.currentTimeMills() returns?
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The current time in milliseconds since midnight, January 1, 1970 GMT (the Unix time)
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Do these expressions yield 0.5? True/False - 1/2.0 - (double) 1/2 - 1.0/2
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True
