Java语言程序设计(基础篇)(原书第10版) 第四章编程练习题
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2024-03-02 11:57:22
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Java语言程序设计(基础篇)(原书第10版) 第四章编程练习题
心血来潮补一下之前没做完的课后题，争取全部做完，欢迎大家评论指正。
目录
- Java语言程序设计(基础篇)(原书第10版) 第四章编程练习题
- 4-1 几何：五边形的面积
- 4-2 几何：最大圆距离
- 4-3 几何：估算面积
- 4-4 几何：六边形面积
- 4-5 几何：正多边形的面积
- 4-6 圆上的随机点
- 4-7 顶点坐标
- 4-8 给出ASCLL码对应的字符
- 4-9 给出字符的Unicode码
- 4-10 猜测生日
- 4-11 十进制转十六进制
- 4-12 十六进制转二进制
- 4-13 判断元音还是辅音
- 4-14 转换字母等级为数字
- 4-15 电话键盘
- 4-16 随机字符
- 4-17 一个月中的日期
- 4-18 学生的专业和状况
- 4-19 商业：检测ISBN-10
- 4-20 字符串处理
- 4-21 检查SSN
- 4-22 检测子串
- 4-23 财务应用：酬金
- 4-24 对三个城市排序
- 4-25 生成车牌号码
- 4-26 财务应用：货币单位
** 需要书籍或者相关资料可以私聊！！！**
4-1 几何：五边形的面积
import java.util.Scanner;
public class Program4_1 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.print("Enter the length from the center to a vertex:");
double r = input.nextDouble();
double s = 2 * r * Math.sin(Math.PI/5.0);
double area = 5 * s * s / (4 * Math.tan(Math.PI/5));
System.out.printf("The area of the pentagon is %.2f\n",area);
}
}
4-2 几何：最大圆距离
import java.util.Scanner;
public class Program4_2 {
public static void main(String[] args) {
final double R = 6371.01;
Scanner input = new Scanner(System.in);
System.out.print("Enter point 1 (latitude and longitude) in degrees: ");
double x1 = Math.toRadians(input.nextDouble());
double y1 = Math.toRadians(input.nextDouble());
System.out.print("Enter point 2 (latitude and longitude) in degrees: ");
double x2 = Math.toRadians(input.nextDouble());
double y2 = Math.toRadians(input.nextDouble());
double d = R * Math.acos(Math.sin(x1) * Math.sin(x2) + Math.cos(x1) * Math.cos(x2) * Math.cos(y1 - y2));
System.out.println("The distance between the two points is " + d + " km");
}
}
4-3 几何：估算面积
public class Program4_3 {
public static void main(String[] args) {
final double R = 6371.01;
double x1 = Math.toRadians(33.78);
double y1 = Math.toRadians(-84.34);
double x2 = Math.toRadians(28.57);
double y2 = Math.toRadians(-81.37);
double x3 = Math.toRadians(32.04);
double y3 = Math.toRadians(-81.08);
double x4 = Math.toRadians(35.20);
double y4 = Math.toRadians(-80.83);
double d1 = R * Math.acos(Math.sin(x1) * Math.sin(x2) + Math.cos(x1) * Math.cos(x2) * Math.cos(y1 - y2));
double d2 = R * Math.acos(Math.sin(x2) * Math.sin(x3) + Math.cos(x2) * Math.cos(x3) * Math.cos(y2 - y3));
double d3 = R * Math.acos(Math.sin(x1) * Math.sin(x3) + Math.cos(x1) * Math.cos(x3) * Math.cos(y1 - y3));
double s1 = (d1 + d2 + d3) / 2.0;
double area1 = Math.pow(s1 * (s1 - d1) * (s1 - d2) * (s1 - d3), 0.5);
double d4 = R * Math.acos(Math.sin(x1) * Math.sin(x4) + Math.cos(x1) * Math.cos(x4) * Math.cos(y1 - y4));
double d5 = R * Math.acos(Math.sin(x4) * Math.sin(x3) + Math.cos(x4) * Math.cos(x3) * Math.cos(y4 - y3));
double d6 = d3;
double s2 = (d4 + d5 + d6) / 2.0;
double area2 = Math.pow(s2 * (s2 - d4) * (s2 - d5) * (s2 - d6), 0.5);
System.out.println("The area of four country is " + (area1 + area2));
}
}
4-4 几何：六边形面积
import java.util.Scanner;
public class Program4_4 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the side: ");
double s = input.nextDouble();
double area = 6 * s * s / (4 * Math.tan(Math.PI / 6.0));
System.out.printf("The area of the hexagon is %.2f\n", area);
}
}
4-5 几何：正多边形的面积
import java.util.Scanner;
public class Program4_5 {
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of sides:");
int n = input.nextInt();
System.out.print("Enter the side:");
double s = input.nextDouble();
double area = n * s * s / (4 * Math.tan(Math.PI / 5));
System.out.println("The area of the polygon is " + area);
}
}
4-6 圆上的随机点
public class Program4_6 {
public static void main(String[] args) {
// TODO Auto-generated method stub
double m = (double)(Math.toRadians((int)(Math.random() * 360)));
double aX = Math.round(40 * Math.cos(m) * 100) / 100.00;
double aY = Math.round(40 * Math.sin(m) * 100) / 100.00;
m = (double)(Math.toRadians((int)(Math.random() * 360)));
double bX = Math.round(40 * Math.cos(m) * 100) / 100.00;
double bY = Math.round(40 * Math.sin(m) * 100) / 100.00;
m = (double)(Math.toRadians((int)(Math.random() * 360)));
double cX = Math.round(40 * Math.cos(m) * 100) / 100.00;
double cY = Math.round(40 * Math.sin(m) * 100) / 100.00;
double a = Math.sqrt((cX - bX) * (cX - bX) + (cY - bY) * (cY - bY));
double b = Math.sqrt((cX - aX) * (cX - aX) + (cY - aY) * (cY - aY));
double c = Math.sqrt((bX - aX) * (bX - aX) + (bY - aY) * (bY - aY));
double A = Math.toDegrees(Math.acos((a*a - b*b - c*c) / (-2 * b * c)));
double B = Math.toDegrees(Math.acos((b*b - a*a - c*c) / (-2 * a * c)));
double C = Math.toDegrees(Math.acos((c*c - a*a - b*b) / (-2 * a * b)));
System.out.println("(" + aX + ", " + aY + ")");
System.out.println("(" + bX + ", " + bY + ")");
System.out.println("(" + cX + ", " + cY + ")");
System.out.println( a );
System.out.println( b );
System.out.println( c );
System.out.println("The three angles are " + Math.round(A * 100) / 100.00 + ", " +
Math.round(B * 100) / 100.00 + ", " + Math.round(C * 100) / 100.00);
}
}
4-7 顶点坐标
import java.util.Scanner;
public class Program4_7 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the radius of the bounding circle: ");
double radius = input.nextDouble();
System.out.println("The coordinates of five points on the pentagon are: ");
double a = Math.PI / 2.0;
for(int i = 1; i <= 5; i++){
System.out.printf("(%.4f, %.4f)\n", radius * Math.cos(a), radius * Math.sin(a));
a += Math.toRadians(360 / 5);
}
}
}
4-8 给出ASCLL码对应的字符
import java.util.Scanner;
public class Program4_8 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter an ASCLL code: ");
int a = input.nextInt();
System.out.printf("The character for ASCLL code %d is %c\n", a, a);
}
}
4-9 给出字符的Unicode码
import java.util.Scanner;
public class Program4_9 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.print("Enter a character: ");
String s = input.nextLine();
char a = s.charAt(0);
System.out.printf("The Unicode for the character %c is %d\n", a, (int)a);
}
}
4-10 猜测生日
import java.util.Scanner;
public class Program4_10 {
public static void main(String[] args) {
String set1 =
" 1 3 5 7\n" +
" 9 11 13 15\n" +
"17 19 21 23\n" +
"25 27 29 31";
String set2 =
" 2 3 6 7\n" +
"10 11 14 15\n" +
"18 19 22 23\n" +
"26 27 30 31";
String set3 =
" 4 5 6 7\n" +
"12 13 14 15\n" +
"20 21 22 23\n" +
"28 29 30 31";
String set4 =
" 8 9 10 11\n" +
"12 13 14 15\n" +
"24 25 26 27\n" +
"28 29 30 31";
String set5 =
"16 17 18 19\n" +
"20 21 22 23\n" +
"24 25 26 27\n" +
"28 29 30 31";
int day = 0;
// Create a Scanner
Scanner input = new Scanner(System.in);
// Prompt the user to answer questions
System.out.print("Is your birthday in Set1?\n");
System.out.print(set1);
System.out.print("\nEnter N for No and Y for Yes: ");
char answer = input.next().charAt(0);
if (answer == 'Y')
day += 1;
// Prompt the user to answer questions
System.out.print("\nIs your birthday in Set2?\n");
System.out.print(set2);
System.out.print("\nEnter 0 for No and 1 for Yes: ");
answer = input.next().charAt(0);
if (answer == 'Y')
day += 2;
// Prompt the user to answer questions
System.out.print("Is your birthday in Set3?\n");
System.out.print(set3);
System.out.print("\nEnter 0 for No and 1 for Yes: ");
answer = input.next().charAt(0);
if (answer == 'Y')
day += 4;
// Prompt the user to answer questions
System.out.print("\nIs your birthday in Set4?\n");
System.out.print(set4);
System.out.print("\nEnter 0 for No and 1 for Yes: ");
answer = input.next().charAt(0);
if (answer == 'Y')
day += 8;
// Prompt the user to answer questions
System.out.print("\nIs your birthday in Set5?\n");
System.out.print(set5);
System.out.print("\nEnter 0 for No and 1 for Yes: ");
answer = input.next().charAt(0);
if (answer == 'Y')
day += 16;
System.out.println("\nYour birthday is " + day + "!");
}
}
4-11 十进制转十六进制
import java.util.Scanner;
public class Program4_11 {
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.print("Enter a decimal value (0 to 15): ");
int a = input.nextInt();
if(a <= 15 && a >= 0){
if(a <= 9)
System.out.println("The hex value is " + a);
else
System.out.println("The hex value is " + (char)(a-10+'A'));
}
else
System.out.println(a + " is an invalid input");
}
}
4-12 十六进制转二进制
import java.util.Scanner;
public class Program4_12 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a hex digit: ");
String s = input.next();
char c = s.charAt(0);
if(s.length() == 1 && (Character.isDigit(c) || (c >= 'A' && c <= 'F'))){
int num;
if(Character.isLetter(c))
num = 10 + c - 'A';
else
num = c - '0';
String ans = Integer.toBinaryString(num);
System.out.printf("The binary value is %s\n", ans);
}else
System.out.printf("%s is an invalid input\n", s);
}
}
4-13 判断元音还是辅音
import java.util.Scanner;
public class Program4_13 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a letter: ");
String s = input.next();
char c = s.charAt(0);
if(s.length() > 1 || !Character.isLetter(c))
System.out.println(s + " is an invalid input");
else{
char m = Character.toLowerCase(c);
if(m == 'a' || m == 'e' || m == 'i' || m == 'o' || m == 'u')
System.out.println(c + " is a vowel");
else
System.out.println(c + " is a consonant");
}
}
}
4-14 转换字母等级为数字
import java.util.Scanner;
public class Program4_14 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.print("Enter a letter grade: ");
String s = input.nextLine();
char c = s.charAt(0);
if(s.length() == 1 && Character.isLetter(c)){
switch (c){
case 'A':
case 'B':
case 'C':
case 'D':
System.out.printf("The numeric value for grade %c is %d\n", c, 4 + 'A' - c);
break;
case 'F':
System.out.println("The numeric value for grade F is 0");
break;
default:
System.out.println(s + " is an invalid input");
}
}
else
System.out.println(s + " is an invalid input");
}
}
4-15 电话键盘
import java.util.Scanner;
public class Program4_15 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a letter: ");
String s = input.next();
char c = s.charAt(0);
if(s.length() == 1 && Character.isLetter(c)){
c = Character.toLowerCase(c);
int num = 2 + (c - 'a') / 3;
if(num == 10) // z or 'Z'
num--;
System.out.println("The corresponding number is " + num);
}else
System.out.println(s + " is an invalid input");
}
}
4-16 随机字符
public class Program4_16 {
public static void main(String[] args) {
int random = (int)(Math.random() * 26);
char c = (char) ('A' + random);
System.out.println("The random character is " + c);
}
}
4-17 一个月中的日期
import java.util.Scanner;
public class Program4_17 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.print("Enter a year: ");
int year = input.nextInt();
System.out.print("Enter a month: ");
String month = input.next();
if(month.equals("Jan") || month.equals("Mar") || month.equals("May") ||
month.equals("Jul") || month.equals("Aug") || month.equals("Oct") || month.equals("Dem"))
System.out.println(month + " " + year + " has 31 days");
else if(month.equals("Apr") || month.equals("Jun") || month.equals("Sep") || month.equals("Nov"))
System.out.println(month + " " + year + " has 30 days");
else if(month.equals("Feb")){
if((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)
System.out.println(month + " " + year + " has 29 days");
else
System.out.println(month + " " + year + " has 28 days");
}
}
}
4-18 学生的专业和状况
import java.util.Scanner;
public class Program4_18 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter two characters: ");
String s = input.next();
char c1 = s.charAt(0), c2 = s.charAt(1);
if(s.length() == 2){
if((c1 == 'M' || c1 == 'C' || c1 == 'I') && c2 >= '1' && c2 <= '4'){
if(c1 == 'M')
System.out.print("Mathematics ");
else if(c1 == 'C')
System.out.print("Computer Science ");
else
System.out.print("Information Technology ");
switch (c2){
case '1':
System.out.println("Freshman");
break;
case '2':
System.out.println("Sophomore");
break;
case '3':
System.out.println("Junior");
break;
case '4':
System.out.println("Senior");
break;
}
}else
System.out.println("Invalid input");
}else
System.out.println("Invalid input");
}
}
4-19 商业：检测ISBN-10
import java.util.Scanner;
public class Program4_19 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the first 9 digits of an ISBN as integer: ");
String s = input.next();
int d10 = ((s.charAt(0) - '0') + (s.charAt(1) - '0')*2 + (s.charAt(2) - '0')*3 + (s.charAt(3) - '0')*4
+ (s.charAt(4) - '0')*5 + (s.charAt(5) - '0')*6 + (s.charAt(6) - '0')*7 + (s.charAt(7) - '0')*8
+ (s.charAt(8) - '0')*9) % 11;
if(d10 == 10)
System.out.println("The ISBN-10 number is " + s + "X");
else
System.out.println("The ISBN-10 number is " + s + d10);
}
}
4-20 字符串处理
import java.util.Scanner;
public class Program4_20 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.print("Please enter a string :");
String str = input.next();
char a = str.charAt(0);
int len = str.length();
System.out.println("The first letter of the string is " + a);
System.out.println("The length of the string is " + len);
}
}
4-21 检查SSN
import java.util.Scanner;
public class Program4_21 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a SSN: ");
String ssn = input.next();
boolean flag = true;
int len = ssn.length();
if(len != 11)
flag = false;
else{
if(Character.isDigit(ssn.charAt(0)) && Character.isDigit(ssn.charAt(1))
&& Character.isDigit(ssn.charAt(2)) && Character.isDigit(ssn.charAt(4))
&& Character.isDigit(ssn.charAt(5)) && Character.isDigit(ssn.charAt(7))
&& Character.isDigit(ssn.charAt(8)) && Character.isDigit(ssn.charAt(9))
&& Character.isDigit(ssn.charAt(10)) && ssn.charAt(3) == '-' && ssn.charAt(6) == '-')
flag = true;
else flag = false;
}
if(flag == true)
System.out.println(ssn + " is a valid social security number");
else
System.out.println(ssn + " is an invalid social security number");
}
}
4-22 检测子串
import java.util.Scanner;
public class Program4_22 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.print("Enter string s1: ");
String s1 = input.nextLine();
System.out.print("Enter string s2: ");
String s2 = input.nextLine();
if(s1.indexOf(s2) != -1)
System.out.println(s2 + " is a substring of " + s1);
else
System.out.println(s2 + " is not a substring of " + s1);
}
}
4-23 财务应用：酬金
import java.util.Scanner;
public class Program4_23 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter employee's name: ");
String name = input.next();
System.out.print("Enter number of hours worked in a week: ");
double hours = Double.parseDouble(input.next());
System.out.print("Enter hourly pay rate: ");
double pay = Double.parseDouble(input.next());
System.out.print("Enter federal tax withholding rate: ");
double federal = Double.parseDouble(input.next());
System.out.print("Enter state tax withholding rate: ");
double state = Double.parseDouble(input.next());
System.out.println("Employee Name: %" + name);
System.out.println("Hours Worked: " + hours);
System.out.println("Pay Rate: $" + pay);
System.out.println("Gross Pay: $" + pay * hours);
System.out.println("Deduction:");
System.out.println(" Federal Withholding (" + federal*100 + "%): $" + pay * hours * federal);
System.out.println(" State Withholding (" + state*100 + "%): $" + pay * hours * state);
System.out.println(" Total Deduction: $" + (pay * hours * federal + pay * hours * state));
System.out.println("Net Pay: $" + (pay * hours - pay * hours * federal - pay * hours * state));
}
}
4-24 对三个城市排序
import java.util.Scanner;
public class Program4_24 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the first city: ");
String s1 = input.nextLine();
System.out.print("Enter the second city: ");
String s2 = input.nextLine();
System.out.print("Enter the third city: ");
String s3 = input.nextLine();
if(s1.compareTo(s2) > 0){
String temp = s1;
s1 = s2;
s2 = temp;
}
if(s2.compareTo(s3) > 0){
String temp = s2;
s2 = s3;
s3 = temp;
}
if(s1.compareTo(s2) > 0){
String temp = s1;
s1 = s2;
s2 = temp;
}
System.out.println("The three cities in alphabetical order are " + s1 + " " + s2 + " " + s3);
}
}
4-25 生成车牌号码
public class Program4_25 {
public static void main(String[] args) {
// TODO Auto-generated method stub
int i;
for(i = 0; i < 3;i++) {
char a;
a = (char) (Math.random()*26 + 'A');
System.out.print(a);
}
for(int j = 0;j < 4;j++) {
int b = (int) (Math.random()*10);
System.out.print(b);
}
}
}
4-26 财务应用：货币单位
import java.util.Scanner;
public class Program4_26 {
public static void main(String[] args) {
// Create a Scanner
Scanner input = new Scanner(System.in);
// Receive the amount
System.out.print("Enter an amount in double, for example 11.56: ");
String amount = input.next();
int index = amount.indexOf('.');
int remainingAmount = (int)(Integer.parseInt(amount.substring(0, index)) * 100
+ Integer.parseInt(amount.substring(index + 1)));
// 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
System.out.println("Your amount " + amount + " consists of");
System.out.println(" " + numberOfOneDollars + " dollars");
System.out.println(" " + numberOfQuarters + " quarters ");
System.out.println(" " + numberOfDimes + " dimes");
System.out.println(" " + numberOfNickels + " nickels");
System.out.println(" " + numberOfPennies + " pennies");
}
}
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