Java语言程序设计(基础篇)(原书第10版) 第五章编程练习题
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2022-04-02 23:03:03
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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
- 5-1 统计正数和负数的个教然后计算这些数的平均值
- 5-2 重复加法
- 5-3 将千克转换成磅
- 5-4 将英里转换成千米
- 5-5 千克与磅之间的互换
- 5-6 英里与千米之间的互换
- 5-7 财务应用程序：计算将来的学费
- 5-8 找出最高分
- 5-9 找出两个分教最高的学生
- 5-10 找出能被5和6整除的数
- 5-11 找出能被5或6整除，但不能被两者同时整除的数
- 5-12 求满足n^2^>12000的n的最小值
- 5-13 求满足n^3^<12000的n的最大值
- 5-14 计算最大公约数
- 5-15 显示ACSII码字符表
- 5-16 找出一个整数的因子
- 5-17 显示金字塔
- 5-18 使用循环语句打印4个图案
- 5-19 打印金字塔形的数字
- 5-20 打印2到1000之间的素数
- 5-21 财务应用程序：比较不同利率下的贷款
- 5-22 财务应用程序：显示分期还贷时间表
- 5-23 示例抵消错误
- 5-24 数列求和
- 5-25 计算π
- 5-26 计算e
- 5-27 显示闰年
- 5-28 显示每月第一天是星期几
- 5-29 显示日历
- 5-30 财务应用程序：复利值
- 5-31 财务应用程序：计算CD价值
- 5-32 游戏：**
- 5-33 完全数
- 5-34 游戏：石头、剪刀、布
- 5-35 加法
- 5-36 商业应用程序：检测ISBN
- 5-37 十进制到二进制
- 5-38 十进制到八进制
- 5-39 财务应用程序：求出销售总额
- 5-40 模拟：正面或反面
- 5-41 最大数的出现次数
- 5-42 财务应用程序：求出销售额
- 5-43 数学方面：组合
- 5-44 计算机体系结构：比特级的操作
- 5-45 统计：计算平均值和标准方差
- 5-46 倒排一个字符串
- 5-47 商业：检测ISBN-13
- 5-48 处理字符串
- 5-49 对元音和辅音进行计数
- 5-50 对大写字母计数
- 5-51 最长的共同前缀
需要书籍或者相关资料可以私聊！！！
5-1 统计正数和负数的个教然后计算这些数的平均值
import java.util.Scanner;
public class Program5_1 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter an integer, the input ends if it is 0: ");
int a = input.nextInt();
int sum = 0,count1 = 0,count2 = 0;
double average;
while(a != 0) {
sum += a;
if(a > 0)
count1++;
else
count2++;
a = input.nextInt();
}
average = sum * 1.0 / (count1 + count2);
System.out.println("The number of positives is " + count1);
System.out.println("The number of negatives is " + count2);
System.out.println("The total is " + sum);
System.out.println("The average is " + average);
input.close();
}
}
5-2 重复加法
import java.util.Scanner;
public class Program5_2 {
public static void main(String[] args) {
final int NUMBER_OF_QUESTIONS = 10; // Number of questions
int correctCount = 0; // Count the number of correct answers
int count = 0; // Count the number of questions
long startTime = System.currentTimeMillis();
String output = ""; // output string is initially empty
Scanner input = new Scanner(System.in);
while (count < NUMBER_OF_QUESTIONS) {
int number1 = (int)(Math.random() * 15) + 1;
int number2 = (int)(Math.random() * 15) + 1;
System.out.print(
"What is " + number1 + " + " + number2 + "? ");
int answer = input.nextInt();
if (number1 + number2 == answer) {
System.out.println("You are correct!");
correctCount++;
}
else
System.out.println("Your answer is wrong.\n" + number1
+ " + " + number2 + " should be " + (number1 + number2));
// Increase the count
count++;
output += "\n" + number1 + "+" + number2 + "=" + answer +
((number1 + number2 == answer) ? " correct" : " wrong");
}
long endTime = System.currentTimeMillis();
long testTime = endTime - startTime;
System.out.println("Correct count is " + correctCount +
"\nTest time is " + testTime / 1000 + " seconds\n" + output);
input.close();
}
}
5-3 将千克转换成磅
public class Program5_3 {
public static void main(String[] args) {
System.out.printf("%-8s%5s\n", "千克", "磅");
for (int i = 1; i <= 199; i += 2)
System.out.printf("%-10d%5.1f\n", i, i*2.2);
}
}
5-4 将英里转换成千米
public class Program5_4 {
public static void main(String[] args) {
System.out.printf("%-8s%5s\n", "英里", "千米");
for (int i = 1; i <= 10; i++)
System.out.printf("%-10d%7.3f\n", i, i*1.609);
}
}
5-5 千克与磅之间的互换
public class Program5_5 {
public static void main(String[] args) {
System.out.printf("%-8s%5s %-8s%5s\n", "千克", "磅", "磅", "千克");
for (int i = 1, j = 20; i <= 199; i += 2, j += 5) {
System.out.printf("%-10d%5.1f ", i, i * 2.2);
System.out.printf("%-10d%5.2f\n", j, j / 2.2);
}
}
}
5-6 英里与千米之间的互换
public class Program5_6 {
public static void main(String[] args) {
System.out.printf("%-8s%5s %-8s%5s\n", "英里", "千米", "千米", "英里");
for (int i = 1, j = 20; i <= 10; i++, j += 5) {
System.out.printf("%-10d%7.3f ", i, i * 1.609);
System.out.printf("%-10d%7.3f\n", j, j / 1.609);
}
}
}
5-7 财务应用程序：计算将来的学费
public class Program5_7 {
public static void main(String[] args) {
// TODO Auto-generated method stub
double m = 10000;
for(int i = 1;i <= 10;i++)
m *= 1.05;
System.out.println("The tuition after 10 years is " + ((int)(m * 100) / 100.00));
double sum = m;
for(int i = 1;i <= 3;i++){
m *= 1.05;
sum += m;
}
System.out.println("The tuition for 4 years after 10 years is " + ((int)(sum * 100) / 100.00));
}
}
5-8 找出最高分
import java.util.Scanner;
public class Program5_8 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of students: ");
int n = input.nextInt();
int maxScore = 0;
String maxName = null;
for (int i = 1; i <= n; i++) {
System.out.print(i + " name and score: ");
String name = input.next();
int score = input.nextInt();
if(maxScore < score){
maxScore = score;
maxName = name;
}
}
System.out.println("The highest score is " + maxName + " : " + maxScore);
input.close();
}
}
5-9 找出两个分教最高的学生
import java.util.Scanner;
public class Program5_9 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of students: ");
int n = input.nextInt();
System.out.print("1 name and score: ");
String Name1 = input.next();
int score1 = input.nextInt();
System.out.print("2 name and score: ");
String Name2 = input.next();
int score2 = input.nextInt();
int max1Score,max2Score;
String max1Name,max2Name;
if(score1 >= score2) {
max1Score = score1;
max1Name = Name1;
max2Score = score2;
max2Name = Name2;
}
else {
max1Score = score2;
max1Name = Name2;
max2Score = score1;
max2Name = Name1;
}
for(int i = 3;i <= n;i++) {
System.out.print(i + " name and score: ");
Name1 = input.next();
score1 = input.nextInt();
if(score1 >= max1Score) {
max2Score = max1Score;
max2Name = max1Name;
max1Score = score1;
max1Name = Name1;
}
else if(score1 >= max2Score) {
max2Score = score1;
max2Name = Name1;
}
}
System.out.println("The highest score is " + max1Name + " : " + max1Score);
System.out.println("The second highest score is " + max2Name + " : " + max2Score);
input.close();
}
}
5-10 找出能被5和6整除的数
public class Program5_10 {
public static void main(String[] args) {
final int numberPerLine = 10;
int cnt = 0;
for (int i = 100; i <= 1000; i++) {
if (i % 5 == 0 && i % 6 == 0) {
cnt++;
System.out.printf("%-6d", i);
if(cnt % 10 == 0)
System.out.println();
}
}
}
}
5-11 找出能被5或6整除，但不能被两者同时整除的数
public class Program5_11 {
public static void main(String[] args) {
final int NUMBER_PER_LINE = 10;
int cnt = 0;
for (int i = 100; i <= 200; i++) {
if (i % 5 == 0 ^ i % 6 == 0) {
cnt++;
System.out.printf("%-6d", i);
if(cnt % NUMBER_PER_LINE == 0)
System.out.println();
}
}
}
}
5-12 求满足n2>12000的n的最小值
public class Program5_12 {
public static void main(String[] args) {
// TODO Auto-generated method stub
int n = 1;
while(n*n <= 12000)
n++;
System.out.println(n);
}
}
5-13 求满足n3<12000的n的最大值
public class Program5_13 {
public static void main(String[] args) {
int n = 1;
while(n*n*n < 12000)
n++;
System.out.println(n-1);
}
}
5-14 计算最大公约数
import java.util.Scanner;
public class Program5_14 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter two numbers : ");
int n1 = input.nextInt();
int n2 = input.nextInt();
int d = Math.min(n1, n2);
while(n1 % d != 0 || n2 % d != 0)
d--;
System.out.printf("The gcd of %d and %d is %d", n1, n2, d);
input.close();
}
}
5-15 显示ACSII码字符表
public class Program5_15 {
public static void main(String[] args) {
final int NUMBER_PER_LINE = 10;
int cnt = 0;
for(char i = '!'; i <= '~'; i++){
System.out.print(i + " ");
cnt++;
if(cnt % NUMBER_PER_LINE == 0)
System.out.println();
}
}
}
5-16 找出一个整数的因子
import java.util.Scanner;
public class Program5_16 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.print("Enter a number: ");
int n = input.nextInt();
System.out.print("Factors of " + n + " is : ");
for(int i = 2;n != 1;i++) {
while(n % i == 0) {
n /= i;
System.out.print(i + " ");
}
}
System.out.println();
input.close();
}
}
5-17 显示金字塔
import java.util.Scanner;
public class Program5_17 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of lines: ");
int n = input.nextInt();
for(int i = 1;i <= n;i++) {
for(int j = 1;j <= 2*(n-i);j++)
System.out.print(" ");
for(int m = i;m >= 1;m--)
System.out.print(m + " ");
for(int k = 2;k <= i;k++)
System.out.print(k + " ");
System.out.println();
}
input.close();
}
}
5-18 使用循环语句打印4个图案
import java.util.Scanner;
public class Program5_18 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of lines: ");
int n = input.nextInt();
System.out.println("Pattern 1:");
for(int i = 1; i <= n; i++) {
for (int j = 1; j <= i; j++)
System.out.print(j + " ");
System.out.println();
}
System.out.println();
System.out.println("Pattern 2:");
for(int i = 1; i <= n; i++) {
for (int j = 1; j <= n - i + 1; j++)
System.out.print(j + " ");
System.out.println();
}
System.out.println();
System.out.println("Pattern 3:");
for(int i = 1; i <= n; i++) {
for (int j = 1; j <= n - i; j++)
System.out.print(" ");
for (int j = i; j >= 1; j--)
System.out.print(j + " ");
System.out.println();
}
System.out.println();
System.out.println("Pattern 4:");
for(int i = 1; i <= n; i++) {
for (int j = 1; j < i; j++)
System.out.print(" ");
for (int j = 1; j <= n - i + 1; j++)
System.out.print(j + " ");
System.out.println();
}
input.close();
}
}
5-19 打印金字塔形的数字
public class Program5_19 {
public static void main(String[] args) {
// TODO Auto-generated method stub
int n = 8;
for(int i = 1;i <= n;i++) {
for(int j = 1;j <= 2*(n-i);j++)
System.out.print(" ");
int r = (int) Math.pow(2.0,i-1);
for(int m = 1;m <= i;m++)
System.out.printf("%4d", 1 << (m-1));
for(int k = i-1;k >= 1;k--)
System.out.printf("%4d", 1 << (k-1));
System.out.println();
}
}
}
5-20 打印2到1000之间的素数
public class Program5_20 {
public static void main(String[] args) {
// TODO Auto-generated method stub
final int NUMBER_OF_PRIMES_PER_LINE = 8; // Display 10 per line
int count = 0; // Count the number of prime numbers
int max = 1000;
// Repeatedly find prime numbers
for(int i = 2;i <= max;i++){
// Assume the number is prime
boolean isPrime = true; // Is the current number prime?
// Test if number is prime
for (int j = 2; j < i / 2; j++) {
if (i % j == 0) { // If true, number is not prime
isPrime = false; // Set isPrime to false
break; // Exit the for loop
}
}
// Print the prime number and increase the count
if(isPrime == true) {
count++; // Increase the count
if (count % NUMBER_OF_PRIMES_PER_LINE == 0)
// Print the number and advance to the new line
System.out.println(i);
else
System.out.print(i + " ");
}
}
}
}
5-21 财务应用程序：比较不同利率下的贷款
import java.util.Scanner;
public class Program5_21 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Loan Amount: ");
double loanAmount = input.nextDouble();
System.out.print("Number of years: ");
int years = input.nextInt();
System.out.printf("%-20s%-20s%s\n", "Interest Rate", "Monthly Payment", "Total Payment");
for (double i = 5.0; i <= 8.0; i += 1.0/8) {
double monthlyRate = i / 1200.0;
double monthlyPayment = loanAmount * monthlyRate / (1 - 1 / Math.pow(1+monthlyRate, years * 12));
System.out.printf("%.3f%% %-20.2f%.2f\n", i, monthlyPayment, monthlyPayment * 12 * years);
}
input.close();
}
}
5-22 财务应用程序：显示分期还贷时间表
import java.util.Scanner;
public class Program5_22 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
//用户输入贷款总额
System.out.print("Loan Amount: ");
Double loanAmount = input.nextDouble();
//用户输入贷款年数
System.out.print("Number of Years: ");
int years = input.nextInt();
//用户输入年利率
System.out.print("Annual Interest Rate: ");
double rate = input.nextDouble();
double monthRate = rate / 1200;
//计算每月还款数额和总还款数额
double monthPay = loanAmount * monthRate / (1 - 1 / Math.pow(1 + monthRate, years * 12));
System.out.printf("\n\nMonthly Payment: %.2f\n", monthPay);
double totalPay = monthPay * 12 * years;
System.out.printf("Total Payment: %.2f\n\n", totalPay);
System.out.println("Payment# Interest Principal Balance");
double total = loanAmount;
for(int i = 1;i <= 12 * years;i++) {
double interest = monthRate * total;
double principal = monthPay - interest;
double balance = total - principal;
System.out.printf("%d\t\t\t\t%.2f\t\t\t%.2f\t\t\t%.2f\n", i, interest, principal, balance);
total = balance;
}
input.close();
}
}
5-23 示例抵消错误
public class Program5_23 {
public static void main(String[] args) {
final int NUMBER = 50000;
System.out.print("From left to right is: ");
double ans1 = 0;
for (int i = 1; i <= NUMBER; i++)
ans1 += 1.0 / i;
System.out.println(ans1);
System.out.print("From right to left is: ");
double ans2 = 0;
for (int i = NUMBER; i >= 1; i--)
ans2 += 1.0 / i;
System.out.println(ans2);
}
}
5-24 数列求和
public class Program5_24 {
public static void main(String[] args) {
// TODO Auto-generated method stub
final int MAX_NUMBER = 97;
double sum = 0;
for(int i = 1;i <= MAX_NUMBER;i += 2)
sum += i * 1.0 / (i + 2);
System.out.println("sum is : " + sum);
}
}
5-25 计算π
public class Program5_25 {
public static void main(String[] args) {
// TODO Auto-generated method stub
//使用数学公式估算pi的值
double pi = 0,sum = 0;
int flag = 1;
for(int n = 10000;n <= 100000;n += 10000) {
System.out.print("n = " + n + " : ");
sum = 0;
for(int i = 1;i <= n;i += 2) {
sum += flag * 1.0 / i;
flag *= -1;
}
pi = 4 * sum;
System.out.println("pi = " + pi);
}
}
}
5-26 计算e
public class Program5_26 {
public static void main(String[] args) {
double e = 1, item = 1;
int flag = 1;
for(int n = 10000;n <= 100000;n += 10000) {
System.out.print("n = " + n + " : ");
for(int i = n-10000+1; i <= n; i++) {
item /= i;
e += item;
}
System.out.println("e = " + e);
}
}
}
5-27 显示闰年
public class Program5_27 {
public static void main(String[] args) {
// TODO Auto-generated method stub
int year1 = 101;
int year2 = 2100;
final int NUMBER_OF_YEARS_PER_LINE = 10;
int count = 0,num = 0;
for(int i = year1;i <= year2;i++) {
if((i % 4 == 0 && i % 100 != 0) || i % 400 == 0) {
count++;
num++;
System.out.print(i + " ");
if(count % NUMBER_OF_YEARS_PER_LINE == 0)
System.out.println();
}
}
System.out.println("\nThe number of leapyears from " + year1 + " to " + year2
+ " is " + num);
}
}
5-28 显示每月第一天是星期几
import java.util.Scanner;
public class Program5_28 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the year: ");
int year = input.nextInt();
System.out.print("Enter the first day of " + year + " as the day of the week (0-6): ");
int day = input.nextInt();
for (int i = 1; i <= 12; i++) {
switch (i){
case 1:
System.out.print("January 1, " + year + " is ");
break;
case 2:
day = (day + 31) % 7;
System.out.print("February 1, " + year + " is ");
break;
case 3:
day = (day + ((year%400 == 0 || (year%100 != 0 && year%4 == 0)) ? 29 : 28)) % 7;
System.out.print("March 1, " + year + " is ");
break;
case 4:
day = (day + 31) % 7;
System.out.print("April 1, " + year + " is ");
break;
case 5:
day = (day + 30) % 7;
System.out.print("May 1, " + year + " is ");
break;
case 6:
day = (day + 31) % 7;
System.out.print("June 1, " + year + " is ");
break;
case 7:
day = (day + 30) % 7;
System.out.print("July 1, " + year + " is ");
break;
case 8:
day = (day + 31) % 7;
System.out.print("August 1, " + year + " is ");
break;
case 9:
day = (day + 31) % 7;
System.out.print("September 1, " + year + " is ");
break;
case 10:
day = (day + 30) % 7;
System.out.print("October 1, " + year + " is ");
break;
case 11:
day = (day + 31) % 7;
System.out.print("November 1, " + year + " is ");
break;
case 12:
day = (day + 30) % 7;
System.out.print("December 1, " + year + " is ");
break;
}
switch (day){
case 0:
System.out.println("Sunday");
break;
case 1:
System.out.println("Monday");
break;
case 2:
System.out.println("Tuesday");
break;
case 3:
System.out.println("Wednesday");
break;
case 4:
System.out.println("Thursday");
break;
case 5:
System.out.println("Friday");
break;
case 6:
System.out.println("Saturday");
break;
}
}
input.close();
}
}
5-29 显示日历
import java.util.Scanner;
public class Program5_29 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int countDayPerLine = 7;
System.out.print("Enter the year: ");
int year = input.nextInt();
System.out.print("Enter the first day of \" + year + \" as the day of the week (0-6): ");
int firstDay = input.nextInt();
int count;
for(int i = 1;i <= 12;i++) {
int day = 1;
int dayCount = 0;
System.out.print("\t\t ");
switch (i){
case 1:
dayCount = 31;
System.out.print("January ");
break;
case 2:
dayCount = (year%400 == 0 || (year%100 != 0 && year%4 == 0)) ? 29 : 28;
System.out.print("February ");
break;
case 3:
dayCount = 31;
System.out.print("March ");
break;
case 4:
dayCount = 30;
System.out.print("April ");
break;
case 5:
dayCount = 31;
System.out.print("May ");
break;
case 6:
dayCount = 30;
System.out.print("June ");
break;
case 7:
dayCount = 31;
System.out.print("July ");
break;
case 8:
dayCount = 31;
System.out.print("August ");
break;
case 9:
dayCount = 30;
System.out.print("September ");
break;
case 10:
dayCount = 31;
System.out.print("October ");
break;
case 11:
dayCount = 30;
System.out.print("November ");
break;
case 12:
dayCount = 31;
System.out.print("December ");
break;
}
System.out.println(year);
System.out.println("------------------------------------------------");
System.out.println("Sun\tMon\tTue\tWed\tThu\tFri\tSat");
for(count = 1; count <= 5*7; count++) {
if(count <= firstDay) System.out.print("\t");
else {
System.out.printf("%-4d", day);
day++;
}
if(day > dayCount)
break;
if(count % countDayPerLine == 0)
System.out.println();
}
System.out.println();
System.out.println();
firstDay = count % 7;
}
input.close();
}
}
5-30 财务应用程序：复利值
import java.util.Scanner;
public class Program5_30 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.print("Please enter the monthly deposit amount: ");
double depositMonthly = input.nextDouble();
System.out.print("Please enter the annual interest rate: ");
double annualRate = input.nextDouble();
double monthlyRate = annualRate / 1200;
System.out.print("Please enter the number of month: ");
int monthNum = input.nextInt();
double deposit = 0;
for(int i = 1; i <= monthNum; i++) {
deposit += depositMonthly;
deposit *= 1 + monthlyRate;
}
System.out.printf("After %d months, the amount is %.3f\n", monthNum, deposit);
input.close();
}
}
5-31 财务应用程序：计算CD价值
import java.util.Scanner;
public class Program5_31 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the initial deposit amount: ");
double amount = input.nextDouble();
System.out.print("Enter annual percentage yield: ");
double monthlyRate = input.nextDouble() / 1200;
System.out.print("Enter maturity period (number of months): ");
int num = input.nextInt();
System.out.println("Month CD Value");
for (int i = 1; i <= num; i++) {
amount += amount * monthlyRate;
System.out.printf("%-8d%.2f\n", i, amount);
}
input.close();
}
}
5-32 游戏：**
import java.util.Scanner;
public class Program5_32 {
public static void main(String[] args) {
// Generate a lottery
int num1 = (int)(Math.random() * 10);
int num2 = (int)(Math.random() * 10);
while(num1 == num2)
num2 = (int)(Math.random() * 10);
int lottery = num1 * 10 + num2;
// Prompt the user to enter a guess
Scanner input = new Scanner(System.in);
System.out.print("Enter your lottery pick (two digits): ");
int guess = input.nextInt();
// Get digits from lottery
int lotteryDigit1 = lottery / 10;
int lotteryDigit2 = lottery % 10;
// Get digits from guess
int guessDigit1 = guess / 10;
int guessDigit2 = guess % 10;
System.out.println("The lottery number is " + lottery);
// Check the guess
if (guess == lottery)
System.out.println("Exact match: you win $10,000");
else if (guessDigit2 == lotteryDigit1
&& guessDigit1 == lotteryDigit2)
System.out.println("Match all digits: you win $3,000");
else if (guessDigit1 == lotteryDigit1
|| guessDigit1 == lotteryDigit2
|| guessDigit2 == lotteryDigit1
|| guessDigit2 == lotteryDigit2)
System.out.println("Match one digit: you win $1,000");
else
System.out.println("Sorry, no match");
input.close();
}
}
5-33 完全数
public class Program5_33 {
public static void main(String[] args) {
System.out.println("Complete number below 10000: ");
for(int n = 2; n <= 10000; n++) {
int sum = 0;
for(int j = 1; j <= n/2; j++)
if(n % j == 0) sum += j;
if(sum == n)
System.out.println(n);
}
}
}
5-34 游戏：石头、剪刀、布
import java.util.Scanner;
public class Program5_34 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
int computerWin = 0;
int playerWin = 0;
while(true) {
int n = (int)(Math.random()*3);
System.out.print("scissor (0), rock (1),paper (2):");
int m = input.nextInt();
System.out.print("The computer is ");
if(n == 0)
{
System.out.print("scissor. ");
if(m == 0) System.out.println("You are scissor too. It is a draw");
if(m == 1) {
System.out.println("You are rock. You won");
playerWin++;
}
if(m == 2) {
System.out.println("You are paper. You lost");
computerWin++;
}
}
if(n == 1)
{
System.out.print("rock. ");
if(m == 0) {
System.out.println("You are scissor. You lost");
computerWin++;
}
if(m == 1) System.out.println("You are rock too. It is a draw");
if(m == 2) {
System.out.println("You are paper. You won");
playerWin++;
}
}
if(n == 2)
{
System.out.print("paper. ");
if(m == 0) {
System.out.println("You are scissor. You won");
playerWin++;
}
if(m == 1) {
System.out.println("You are rock. You lost");
computerWin++;
}
if(m == 2) System.out.println("You are paper too. It is a draw");
}
if(computerWin == 2) {
System.out.println("Game Over! You lost");
break;
}
if(playerWin == 2) {
System.out.println("Game Over! You win");
break;
}
}
input.close();
}
}
5-35 加法
public class Program5_35 {
public static void main(String[] args) {
double sum = 0.0;
for (int i = 1; i <= 624; i++)
sum += 1 / (Math.pow(i, 0.5) + Math.pow(i + 1, 0.5));
System.out.println("sum is " + sum);
}
}
5-36 商业应用程序：检测ISBN
import java.util.Scanner;
public class Program5_36 {
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 sum = 0;
for (int i = 0; i < 9; i++)
sum += (s.charAt(i) - '0') * (i+1);
int d10 = sum % 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);
input.close();
}
}
5-37 十进制到二进制
import java.util.Scanner;
public class Program5_37 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a number: ");
int num = input.nextInt();
int m = num;
String s = "";
while(m > 0){
s = (m % 2) + s;
m /= 2;
}
System.out.println(num + "'s binary is " + s);
input.close();
}
}
5-38 十进制到八进制
import java.util.Scanner;
public class Program5_38 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a number: ");
int num = input.nextInt();
int m = num;
String s = "";
while(m > 0){
s = (m % 8) + s;
m /= 8;
}
System.out.println(num + "'s octal is " + s);
input.close();
}
}
5-39 财务应用程序：求出销售总额
public class Program5_39 {
public static void main(String[] args) {
final int BASIC_SALARY = 5000;
int sales = 10000;
double mySalary = BASIC_SALARY + 5000*0.08 + 5000*0.1 + (sales - 10000) * 0.12;
while(mySalary < 30000){
sales++;
mySalary = BASIC_SALARY + 5000*0.08 + 5000*0.1 + (sales - 10000) * 0.12;
}
System.out.println("The minimum sales you have to complete is " + sales);
}
}
5-40 模拟：正面或反面
public class Program5_40 {
public static void main(String[] args) {
final int TIMES = 1000000;
int cnt1 = 0;
int cnt2 = 0;
for (int i = 0; i < TIMES; i++) {
int n = (int)(Math.random() * 2);
if(n == 1)
cnt1++;
else
cnt2++;
}
System.out.printf("The coin appears %d times on the front\n", cnt1);
System.out.printf("The coin appears %d times on the back\n", cnt2);
}
}
5-41 最大数的出现次数
import java.util.Scanner;
public class Program5_41 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter numbers: ");
int max = 0, count = 0;
int num = input.nextInt();
while(num != 0){
if(num > max){
max = num;
count = 1;
}else if(num == max)
count++;
num = input.nextInt();
}
System.out.println("The largest number is " + max);
System.out.println("The occurrence count of the largest number is " + count);
input.close();
}
}
5-42 财务应用程序：求出销售额
import java.util.Scanner;
public class Program5_42 {
public static void main(String[] args) {
final int BASIC_SALARY = 5000;
Scanner input = new Scanner(System.in);
System.out.print("Enter the commission sought: ");
int commissionSought = input.nextInt();
int sales = 10000;
double mySalary = BASIC_SALARY + 5000*0.08 + 5000*0.1 + (sales - 10000) * 0.12;
for (;mySalary <= commissionSought; sales++)
mySalary = BASIC_SALARY + 5000*0.08 + 5000*0.1 + (sales - 10000) * 0.12;
System.out.println("The minimum sales you have to complete is " + (sales-1));
input.close();
}
}
5-43 数学方面：组合
public class Program5_43 {
public static void main(String[] args) {
final int MAX_NUMBER = 7;
int count = 0;
for (int i = 1; i <= 7; i++)
for(int j = i+1; j <= 7; j++) {
System.out.println(i + " " + j);
count++;
}
System.out.println("The total number of all combinations is " + count);
}
}
5-44 计算机体系结构：比特级的操作
import java.util.Scanner;
public class Program5_44 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter an integer: ");
int num = input.nextInt();
String bits = "";
for (int i = 15; i >= 0; i--)
bits += (num >> i) & 1;
System.out.println("The bits are " + bits);
input.close();
}
}
5-45 统计：计算平均值和标准方差
import java.util.Scanner;
public class Program5_45 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
double sum = 0.0, squareSum = 0.0;
System.out.print("Enter ten numbers: ");
for (int i = 0; i < 10; i++) {
double num = input.nextDouble();
sum += num;
squareSum += num * num;
}
double mean = sum / 10;
double deviation = Math.sqrt((squareSum - sum * sum / 10) / 9);
System.out.printf("The mean is %.2f\n", mean);
System.out.printf("The standard deviation is %.5f\n", deviation);
input.close();
}
}
5-46 倒排一个字符串
import java.util.Scanner;
public class Program5_46 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a string: ");
String str = input.nextLine();
System.out.print("The reversed string is ");
for (int i = str.length()-1; i >= 0; i--)
System.out.print(str.charAt(i));
System.out.println();
input.close();
}
}
5-47 商业：检测ISBN-13
import java.util.Scanner;
public class Program5_47 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the first 12 digits of an ISBN-13 as a string: ");
String isbn = input.next();
int sum = 0,d13 = 0;
if(isbn.length() == 12) {
for(int i = 0; i < 12; i++) {
if(i % 2 == 0)
sum += (int) isbn.charAt(i) - '0';
else
sum += 3 * ((int) isbn.charAt(i) - '0');
}
d13 = (10 - sum % 10) % 10;
isbn += d13;
System.out.println("The ISBN-13 number is " + isbn);
}
else
System.out.println(isbn + " is an invalid input");
input.close();
}
}
5-48 处理字符串
import java.util.Scanner;
public class Program5_48 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a string: ");
String str1 = input.nextLine();
String str2 = "";
for(int i = 0;i < str1.length(); i++)
if(i % 2 == 0)
str2 += str1.charAt(i);
System.out.println(str2);
input.close();
}
}
5-49 对元音和辅音进行计数
import java.util.Scanner;
public class Program5_49 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a string: ");
String str = input.nextLine();
int vowel = 0, consonant = 0;
for (int i = 0; i < str.length(); i++)
if(Character.isLetter(str.charAt(i))){
char c = Character.toLowerCase(str.charAt(i));
if(c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u')
vowel++;
else
consonant++;
}
System.out.println("The number of vowels is " + vowel);
System.out.println("The number of consonants is " + consonant);
input.close();
}
}
5-50 对大写字母计数
import java.util.Scanner;
public class Program5_50 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a string: ");
String str = input.nextLine();
int uppercase = 0;
for (int i = 0; i < str.length(); i++)
if(Character.isUpperCase(str.charAt(i)))
uppercase++;
System.out.println("The number of uppercase letters is " + uppercase);
input.close();
}
}
5-51 最长的共同前缀
import java.util.Scanner;
public class Program5_51 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the first string: ");
String str1 = input.nextLine();
System.out.print("Enter the second string: ");
String str2 = input.nextLine();
if(str1.length() <= str2.length()){
String temp = str1;
str1 = str2;
str2 = temp;
}
String ans = "";
for (int i = 0; i < str2.length(); i++) {
boolean flag = true;
for (int j = 0; j <= i; j++)
if(str1.charAt(j) != str2.charAt(j)){
flag = false;
break;
}
if(flag)
ans = str2.substring(0, i+1);
}
if(ans.length() > 0)
System.out.println("The common prefix is " + ans);
else
System.out.println(str1 + " and " + str2 + " have no common prefix");
input.close();
}
}
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