java语言程序设计基础篇英文8版课后习题答案.doc

public class Exercise1_2 public static void main(String args) System.out.println("Welcome to Java"); System.out.println("Welcome to Java"); System.out.println("Welcome to Java"); System.out.println("Welcome to Java"); System.out.println("Welcome to Java"); public class Exercise1_4 public static void main(String args) System.out.println("a a2 a3"); System.out.println("1 1 1"); System.out.println("2 4 8"); System.out.println("3 9 27"); System.out.println("4 16 64"); public class Exercise1_6 public static void main(String args) System.out.println(1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9); public class Exercise1_8 public static void main(String args) / Display area System.out.println(5.5 * 5.5 * 3.14159); / Display perimeter System.out.println(2 * 5.5 * 3.14159); import javax.swing.JOptionPane;public class Exercise2_1WithDialogBox / Main method public static void main(String args) / Enter a temperatur in Fahrenheit String celsiusString = JOptionPane.showInputDialog(null, "Enter a temperature in Celsius:", "Exercise2_1 Input", JOptionPane.QUESTION_MESSAGE); / Convert string to double double celsius = Double.parseDouble(celsiusString); / Convert it to Celsius double fahrenheit = (9.0 / 5) * celsius + 32; / Display the result JOptionPane.showMessageDialog(null, "The temperature is " + fahrenheit + " in Fahrenheit"); import java.util.Scanner;public class Exercise2_2 public static void main(String args) Scanner input = new Scanner(System.in); / Enter radius of the cylinder System.out.print("Enter radius of the cylinder: "); double radius = input.nextDouble(); / Enter length of the cylinder System.out.print("Enter length of the cylinder: "); double length = input.nextDouble(); double volume = radius * radius * 3.14159 * length; System.out.println("The volume of the cylinder is " + volume); public class Exercise2_4 public static void main(String args) / Prompt the input java.util.Scanner input = new java.util.Scanner(System.in); System.out.print("Enter a number in pounds: "); double pounds = input.nextDouble(); double kilograms = pounds * 0.454; System.out.println(pounds + " pounds is " + kilograms + " kilograms"); / Exercise2_6.java: Summarize all digits in an integer < 1000public class Exercise2_6 / Main method public static void main(String args) java.util.Scanner input = new java.util.Scanner(System.in); / Read a number System.out.print("Enter an integer between 0 and 1000: "); int number = input.nextInt(); / Find all digits in number int lastDigit = number % 10; int remainingNumber = number / 10; int secondLastDigit = remainingNumber % 10; remainingNumber = remainingNumber / 10; int thirdLastDigit = remainingNumber % 10; / Obtain the sum of all digits int sum = lastDigit + secondLastDigit + thirdLastDigit; / Display results System.out.println("The sum of all digits in " + number + " is " + sum); public class Exercise2_8 public static void main(String args) java.util.Scanner input = new java.util.Scanner(System.in); / Enter an ASCII code System.out.print("Enter an ASCII code: "); int code = input.nextInt(); / Display result System.out.println("The character for ASCII code " + code + " is " + (char)code); import java.util.Scanner;public class Exercise2_10 /* Main method */ public static void main(String args) Scanner input = new Scanner(System.in); / Receive the amount entered from the keyboard System.out.print("Enter an amount in double, for example 11.56 "); double amount = input.nextDouble(); int remainingAmount = (int)(amount * 100); / Find the number of one dollars int numberOfOneDollars = remainingAmount / 100; remainingAmount = remainingAmount % 100; / Find the number of quarters in the remaining amount int numberOfQuarters = remainingAmount / 25; remainingAmount = remainingAmount % 25; / Find the number of dimes in the remaining amount int numberOfDimes = remainingAmount / 10; remainingAmount = remainingAmount % 10; / Find the number of nickels in the remaining amount int numberOfNickels = remainingAmount / 5; remainingAmount = remainingAmount % 5; / Find the number of pennies in the remaining amount int numberOfPennies = remainingAmount; / Display results String output = "Your amount " + amount + " consists of n" + numberOfOneDollars + " dollarsn" + numberOfQuarters + " quartersn" + numberOfDimes + " dimesn" + numberOfNickels + " nickelsn" + numberOfPennies + " pennies" System.out.println(output); import javax.swing.JOptionPane;public class Exercise2_12a public static void main(String args) / Obtain input String balanceString = JOptionPane.showInputDialog(null, "Enter balance:"); double balance = Double.parseDouble(balanceString); String interestRateString = JOptionPane.showInputDialog(null, "Enter annual interest rate:"); double annualInterestRate = Double.parseDouble(interestRateString); double monthlyInterestRate = annualInterestRate / 1200; double interest = balance * monthlyInterestRate; / Display output JOptionPane.showMessageDialog(null, "The interest is " + (int)(100* interest) / 100.0); import java.util.Scanner;public class Exercise2_12b public static void main(String args) Scanner input = new Scanner(System.in); / Obtain input System.out.print("Enter balance: "); double balance = input.nextDouble(); System.out.print("Enter annual interest rate: "); double annualInterestRate = input.nextDouble(); double monthlyInterestRate = annualInterestRate / 1200; double interest = balance * monthlyInterestRate; / Display output System.out.println("The interest is " + (int)(100* interest) / 100.0); import java.util.Scanner;public class Exercise2_14 public static void main(String args) Scanner input = new Scanner(System.in); / Prompt the user to enter weight in pounds System.out.print("Enter weight in pounds: "); double weight = input.nextDouble(); / Prompt the user to enter height in inches System.out.print("Enter height in inches: "); double height = input.nextDouble(); double bmi = weight * 0.45359237 / (height * 0.0254 * height * 0.0254); System.out.print("BMI is " + bmi); public class Exercise2_16 public static void main(String args) java.util.Scanner input = new java.util.Scanner(System.in); System.out.print( "Enter the amount of water in kilograms: "); double mass = input.nextDouble(); System.out.print("Enter the initial temperature: "); double initialTemperature = input.nextDouble(); System.out.print( "Enter the final temperature: "); double finalTemperature = input.nextDouble(); double energy = mass * (finalTemperature - initialTemperature) * 4184; System.out.print("The energy needed is " + energy); public class Exercise2_18 / Main method public static void main(String args) System.out.println("a b pow(a, b)"); System.out.println("1 2 " + (int)Math.pow(1, 2); System.out.println("2 3 " + (int)Math.pow(2, 3); System.out.println("3 4 " + (int)Math.pow(3, 4); System.out.println("4 5 " + (int)Math.pow(4, 5); System.out.println("5 6 " + (int)Math.pow(5, 6); import java.util.Scanner;public class Exercise2_20 public static void main(String args) Scanner input = new Scanner(System.in); / Enter the first point with two double values System.out.print("Enter x1 and y1: "); double x1 = input.nextDouble(); double y1 = input.nextDouble(); / Enter the second point with two double values System.out.print("Enter x2 and y2: "); double x2 = input.nextDouble(); double y2 = input.nextDouble(); / Compute the distance double distance = Math.pow(x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2), 0.5); System.out.println("The distance of the two points is " + distance); import java.util.Scanner;public class Exercise2_22 public static void main(String args) Scanner input = new Scanner(System.in); / Enter the side of the hexagon System.out.print("Enter the side: "); double side = input.nextDouble(); / Compute the area double area = 3 * 1.732 * side * side / 2; System.out.println("The area of the hexagon is " + area); import java.util.Scanner;public class Exercise2_24 public static void main(String args) Scanner input = new Scanner(System.in); System.out.print("Enter speed v: "); double v = input.nextDouble(); System.out.print("Enter acceleration a: "); double a = input.nextDouble(); double length = v * v / (2 * a); System.out.println("The minimum runway length for this airplane is " + length + " meters"); public class Exercise3_2 /*Main method*/ public static void main(String args) java.util.Scanner input = new java.util.Scanner(System.in); / Prompt the user to enter an integer System.out.print("Enter an integer: "); int number = input.nextInt(); / Display results System.out.println("Is " + number + " an even number? " + (number % 2 = 0); import javax.swing.*;public class Exercise3_4 public static void main(String args) int number1 = (int)(System.currentTimeMillis() % 100); int number2 = (int)(System.currentTimeMillis() * 7 % 100); ("What is " + number1 + " + " + number2 + "?"); int result = Integer.parseInt(resultString); JOptionPane.showMessageDialog(null, number1 + " + " + number2 + " = " + result + " is " + (number1 + number2 = result); import javax.swing.*;public class Exercise3_5WithJOptionPane public static void main(String args) int number1 = (int)(System.currentTimeMillis() % 10); int number2 = (int)(System.currentTimeMillis() * 7 % 10); int number3 = (int)(System.currentTimeMillis() * 3 % 10); ("What is " + number1 + " + " + number2 + " + " + number3 + "?"); int answer = Integer.parseInt(answerString); JOptionPane.showMessageDialog(null, number1 + " + " + number2 + " + " + number3 + " = " + answer + " is " + (number1 + number2 + number3 = answer); import java.util.Scanner;public class Exercise3_6 public static void main(String args) Scanner input = new Scanner(System.in); / Prompt the user to enter weight in pounds System.out.print("Enter weight in pounds: "); double weight = input.nextDouble(); / Prompt the user to enter height System.out.print("Enter feet: "); double feet = input.nextDouble(); System.out.print("Enter inches: "); double inches = input.nextDouble(); double height = feet * 12 + inches; / Compute BMI double bmi = weight * 0.45359237 / (height * 0.0254) * (height * 0.0254); / Display result System.out.println("Your BMI is " + bmi); if (bmi < 16) System.out.println("You are seriously underweight"); else if (bmi < 18) System.out.println("You are underweight"); else if (bmi < 24) System.out.println("You are normal weight"); else if (bmi < 29) System.out.println("You are over weight"); else if (bmi < 35) System.out.println("You are seriously over weight"); else System.out.println("You are gravely over weight"); public class Exercise3_8 public static void main(String args) java.util.Scanner input = new java.util.Scanner(System.in); / Enter three numbers System.out.print("Enter three integers: "); int num1 = input.nextInt(); int num2 = input.nextInt(); int num3 = input.nextInt(); if (num1 > num2) int temp = num1; num1 = num2; num2 = temp; if (num2 > num3) int temp = num2; num2 = num3; num3 = temp; if (num1 > num2) int temp = num1; num1 = num2; num2 = temp; System.out.println("The sorted numbers are " + num1 + " " + num2 + " " + num3); import javax.swing.JOptionPane;public class Exercise3_10 public static void main(String args) / 1. Generate two random single-digit integers int number1 = (int)(Math.random() * 10); int number2 = (int)(Math.random() * 10); / 2. Prompt the student to answer 搘 ("What is " + number1 + " + " + number2 + "?"); int answer = Integer.parseInt(answerString); / 4. Grade the annser and display the result String replyString; if (number1 + number2 = answer) replyString = "You are correct!" else replyString = "Your answer is wrong.n" + number1 + " + " + number2 + " should be " + (number1 + number2); JOptionPane.showMessageDialog(null, replyString); import java.util.Scanner;public class Exercise3_12 public static void main(String args) Scanner input = new Scanner(System.in); / Prompt the user to enter an integer System.out.print("Enter an integer: "); int number = input.nextInt(); if (number % 5 = 0 && number % 6 = 0) System.out.println(number + " is divisible by both 5 and 6"); else if (number % 5 = 0 number % 6 = 0) System.out.println(number + " is divisible by both 5 and 6, but not both"); else System.out.println(number + " is not divisible by either 5 or 6"); public class Exercise3_14 public static void main(String args) / Obtain the random number 0 or 1 int number = (int)(Math.random() * 2); / Prompt the user to enter a guess java.util.Scanner input = new java.util.Scanner(System.in); System.out.print("Guess head or tail? " + "Enter 0 for head and 1 for tail: "); int guess = input.nextInt(); / Check the guess if (guess = numb