java基础语言课后题答案.docx

1.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); 2.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); 3.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); 4.public class Exercise1_6 public static void main(String args) System.out.println(1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9); 5.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); 6.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); 7.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); 8.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); 9./ 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); 10 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); public class Exercise2_8 public static void main(String args) java.util.Scanner input = new java.util.Scanner(System.in); / E