Quiz Questions
For Chapter 8
THIS PAGE CONTAINS A SAMPLE quiz on material from Chapter 8 of this on-line Java textbook. You should be able to answer these questions after studying that chapter. Sample answers to all the quiz questions can be found here.
Question 1: What does the computer do when it executes the following statement? Try to give as complete an answer as possible.
Color[] pallette = new Color[12];Question 2: What is meant by the basetype of an array?
Question 3: What does it mean to sort an array?
Question 4: What is meant by a dynamic array? What is the advantage of a dynamic array over a regular array?
Question 5: What is the purpose of the following subroutine? What is the meaning of the value that it returns, in terms of the value of its parameter?
static String concat( String[] str ) { if (str == null) return null; String ans = ""; for (int i = 0; i < str.length; i++) { ans = ans + str[i]; return ans; }Question 6: Show the exact output produced by the following code segment.
char[][] pic = new char[6][6]; for (int i = 0; i < 6; i++) for (int j = 0; j < 6; j++) { if ( i == j || i == 0 || i == 5 ) pic[i][j] = '*'; else pic[i][j] = '.'; } for (int i = 0; i < 6; i++) { for (int j = 0; j < 6; j++) System.out.print(pic[i][j]); System.out.println(); }Question 7: Write a complete subroutine that finds the largest value in an array of ints. The subroutine should have one parameter, which is an array of type int[]. The largest number in the array should be returned as the value of the subroutine.
Question 8: Suppose that temperature measurements were made on each day of 1999 in each of 100 cities. The measurements have been stored in an array
int[][] temps = new int[100][365];where temps[c][d] holds the measurement for city number c on the dth day of the year. Write a code segment that will print out the average temperature, over the course of the whole year, for each city. The average temperature for a city can be obtained by adding up all 365 measurements for that city and dividing the answer by 365.0.
Question 9: Suppose that a class, Employee, is defined as follows:
class Employee { String lastName; String firstName; double hourlyWage; int yearsWithCompany; }Suppose that data about 100 employees is already stored in an array:
Employee[] employeeData = new Employee[100];Write a code segment that will output the first name, last name, and hourly wage of each employee who has been with the company for 20 years or more.
Question 10: Suppose that A has been declared and initialized with the statement
double[] A = new double[20];
And suppose that A has already been filled with 20 values. Write a program segment that will find the average of all the non-zero numbers in the array. (The average is the sum of the numbers, divided by the number of numbers. Note that you will have to count the number of non-zero entries in the array.) Declare any variables that you use.
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