Java语言程序设计基础篇编程练习题-第二章
2.1（摄氏温度转华氏温度）
import java.util.Scanner;
public class Test2_01 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a degree in Celsius:");
// double celsius = input.nextDouble();
int celsius = input.nextInt();
input.close();
double fahrenheit = (9.0 / 5) * celsius + 32;
System.out.println(celsius + " Celsius is " + fahrenheit + " Fahrenheit");
}
}
2.2（计算圆柱体的体积）
import java.util.Scanner;
public class Test2_02 {
public static void main(String[] args) {
final double p = 3.1415926;
Scanner input = new Scanner(System.in);
System.out.print("Enter the radius and length of a cylinder: ");
double radius = input.nextDouble();
double length = input.nextDouble();
input.close();
double area = radius * radius * p;
double volume = area * length;
System.out.println("The area is " + area);
System.out.println("The volume is " + volume);
}
}
2.3（将英尺转换为米）
import java.util.Scanner;
public class Test2_03 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a value for feet: ");
double feet = input.nextDouble();
input.close();
double meters = 0.305 * feet;
System.out.println(feet + " feet is " + meters + " meters");
}
}
2.4（将磅转换为千克）
import java.util.Scanner;
public class Test2_04 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter a number in pounds: ");
double pounds = input.nextDouble();
input.close();
double kilograms = pounds * 0.454;
System.out.println(pounds + " pounds is " + kilograms + " kilograms");
}
}
2.5（财务应用程序，计算小费）
import java.util.Scanner;
public class Test2_05 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the subtotal and a gratuity rate:");
double subtotal = input.nextDouble();
double rate = input.nextDouble();
input.close();
double gratuity = rate / 100 * subtotal;
System.out.println("The gratuity is $" + gratuity + " and total is $" + (gratuity + subtotal));
}
}
2.6（求一个整数各位数的和）
import java.util.Scanner;
public class Test2_06 {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.print("Enter a number between 0 and 1000: ");
int number = scan.nextInt();
scan.close();
int num1 = number % 10;
int num2 = number / 10 % 10;
int num3 = number / 100;
int sum = num1 + num2 + num3;
System.out.println("The sum of the digits is " + sum);
}
}
2.7（求出年数）
import java.util.Scanner;
public class Test2_07 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of minutes: ");
int minutes = input.nextInt();
input.close();
int days = minutes / 60 / 24;
int years = days / 365;
int day = days % 365;
System.out.println(minutes + " minuise is approximately " + years + " years and " + day + " days");
}
}
2.8（当前时间）
import java.util.Scanner;
public class Test2_08 {
public static void main(String[] args) {
//获取系统时钟数
long totalMilliseconds = System.currentTimeMillis();
//整除1000得到总秒数
long totalSeconds = totalMilliseconds / 1000;
//总秒数对 60 取余得当现在时间的秒数
long currentSeconds = totalSeconds % 60;
//总秒数对 60 取整得当现在时间的总分钟数
long totalMinutes = totalSeconds / 60;
//总分钟数对 60 取余得当现在时间的分钟数
long currentMinute = totalMinutes % 60;
//总分钟数对 60 取整得当现在时间的总小时数
long totalHours = totalMinutes / 60;
//总小时数对 24 取余得当现在时间的小时数
long currentHour = totalHours % 24;
Scanner input = new Scanner(System.in);
System.out.print("Enter the time zone offset to GMT: ");
int time = input.nextInt();
input.close();
int hour = (int)currentHour + time;
System.out.println("The current time is " + hour + ":" + currentMinute + ":" + currentSeconds);
}
}
2.9（物理，加速度）
import java.util.Scanner;
public class Test2_09 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter v0, v1, and t: ");
double v0 = input.nextDouble();
double v1 = input.nextDouble();
double t = input.nextDouble();
input.close();
double acc = (v1 - v0) / t;
System.out.println("The average acceleration is " + acc);
}
}
2.10（科学，计算能量）
import java.util.Scanner;
public class Test2_10 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the amount of water in kilograms: ");
double m = input.nextDouble();
System.out.print("Enter the initial temperature: ");
double inT = input.nextDouble();
System.out.print("Enter the final temperature: ");
double finalT = input.nextDouble();
input.close();
double Q = m * (finalT - inT) * 4184;
System.out.println("The energy needed is " + Q);
}
}
2.11（人口统计）
import java.util.Scanner;
public class Test2_11 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of years: ");
int years = input.nextInt();
input.close();
int num = 312032486;
int time = 3600 * 24 * 365;
int birth = time / 7;
int die = time / 13;
int in = time / 45;
int change = birth + in - die;
for(int i = 0; i < years; i++) {
num += change;
}
System.out.println("The population in " + years + " years is " + num);
}
}
2.12（物理：求出跑道长度）
import java.util.Scanner;
public class Test2_12 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter speed and acceleration: ");
double speed = input.nextDouble();
double acc = input.nextDouble();
input.close();
double length = (speed * speed) / (2 * acc);
System.out.println("The minmum runway length for this airplane is " + length);
}
}
2.13（财务应用程序：复利值）
import java.util.Scanner;
public class Test2_13 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the monthly saving amount: ");
double amount = input.nextDouble();
input.close();
double value = 0;
for(int i = 0; i < 6; i++) {
value = (amount + value) * (1 + 0.00417);
}
System.out.println("After the sixth month, the account value is $" + value);
}
}
2.14（医疗应用程序：计算BMI）
import java.util.Scanner;
public class Test2_14 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter weight in pounds: ");
double weight = input.nextDouble();
System.out.print("Enter height in inches: ");
double height = input.nextDouble();
input.close();
weight = weight * 0.4539237;
height = height * 0.0254;
double bmi = weight / (height * height);
System.out.println("BMI is " + bmi);
}
}
2.15（几何：两点之间的距离）
import java.util.Scanner;
public class Test2_15 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter x1 and y1: ");
double x1 = input.nextDouble();
double y1 = input.nextDouble();
System.out.print("Enter x2 ang y2: ");
double x2 = input.nextDouble();
double y2 = input.nextDouble();
input.close();
double d1 = Math.pow((x2 - x1),2);
double d2 = Math.pow((y2 - y1),2);
double distance = Math.pow(d1 + d2, 0.5);
System.out.println("The distance between the points is " + distance);
}
}
2.16（几何，六边形面积）
import java.util.Scanner;
public class Test2_16 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the side: ");
double side = input.nextDouble();
input.close();
double area = 3 * Math.pow(3, 0.5) / 2 * side * side;
System.out.println("The area of the hexagon is " + area);
}
}
2.17（科学，风寒温度）
import java.util.Scanner;
public class Test2_17 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the temperature in Fahrenheit between -58F and 41F:");
double temperature = input.nextDouble();
System.out.print("Enter the wind speed (>=2) in miles per hour: ");
int wind = input.nextInt();
input.close();
double d = Math.pow(wind, 0.16);
double t = 35.74 + 0.6215 * temperature - 35.75 * d + 0.4275 * temperature * d;
System.out.println("The wind chill index is " + t);
}
}
2.18（打印表格）
import java.util.Scanner;
public class Test2_18 {
public static void main(String[] args) {
System.out.println("a\tb\tpow(a,b)");
for(int a = 1; a <= 5; a++) {
int b = a + 1;
int pow = (int)(Math.pow(a, b));
System.out.println(a + "\t" + b + "\t" + pow);
}
}
}
2.19（几何：三角形的面积）
import java.util.Scanner;
public class Test2_19 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter three points for a triangle: ");
double x1 = input.nextDouble();
double y1 = input.nextDouble();
double x2 = input.nextDouble();
double y2 = input.nextDouble();
double x3 = input.nextDouble();
double y3 = input.nextDouble();
input.close();
double s1 = Math.pow(Math.pow((x2 - x1),2) + Math.pow((y2 - y1),2), 0.5);
double s2 = Math.pow(Math.pow((x2 - x3),2) + Math.pow((y2 - y3),2), 0.5);
double s3 = Math.pow(Math.pow((x3 - x1),2) + Math.pow((y3 - y1),2), 0.5);
double s = (s1 + s2 + s3) / 2;
double area = Math.pow(s * (s - s1) * (s - s2) * (s - s3), 0.5);
System.out.println("The area of the triangle is " + area);
}
}
2.20（财务应用程序：计算利息）
import java.unit.Scanner;
public class Test2_20 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter balance and interest rate (e.g., 3 for 3%): ");
double balance = input.nextDouble();
double rate = input.nextDouble();
input.close();
double amount = balance * (rate / 1200);
System.out.println("The interest is " + amount);
}
}
2.21（财务应用：计算未来投资值）
import java.util.Scanner;
public class Test2_21 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter investment amount: ");
double amount = input.nextDouble();
System.out.print("Enter annual interest rate in percentage: ");
double rate = input.nextDouble();
System.out.print("Enter number of years:");
int years = input.nextInt();
input.close();
double value = amount * Math.pow((1 + rate/1200), (years * 12));
System.out.println("Accumulated value is $" + value);
}
}
2.22（财务应用：货币单位）
import java.util.Scanner;
public class Test2_22 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the number: ");
int num = input.nextInt();
input.close();
int num1 = num / 100;
int num2 = num % 100;
System.out.println(num + " is " + num1 + " dollars and " + num2 + " cents.");
}
}
2.23（驾驶费用）
import java.util.Scanner;
public class Test2_23 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the driving distance: ");
double distance = input.nextDouble();
System.out.print("Enter miles per gallon: ");
double miles = input.nextDouble();
System.out.print("Enter price per gallon: ");
double price = input.nextDouble();
input.close();
double cost = distance / miles * price;
System.out.println("The cost of driving is $" + cost);
}
}
以上代码均为个人编写，不当之处，悉请指正。