Java程序语言(基础篇)第2章 基本程序设计 编程练习题解答

时间:2023-02-22 21:50:12
 
 
 //编程练习题2.1~2.25
/**
 * 2.1 程序要求:编写程序,从控制台读入double型的摄氏温度,然后将其转换为华氏温度,并且显示结果。
 * 转换公式如下所示:
 * fahrenheit = (9/5) * celsius +32 (华氏度= (9/5) * 摄氏度+32)
 * @作者:wwj
 * 日期:2012/5/6
 * 功能:将摄氏温度转换为华氏温度
 * 
 * 运行结果:
 * Enter a degree in Celsius: 43
 * 43.0 Celsius is 109.4 Fahrenheit
 */
import java.util.Scanner;

public class Exercise2_1 {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		
		//输入一个摄氏温度
		System.out.println("Enter a degree in Celsius: ");
		double celsius = input.nextDouble();
		
		//转换为华氏温度
		double fahrenheit = (9.0/5) * celsius + 32;
		
		//输出结果
		System.out.println(celsius + " Celsius is " + fahrenheit + " Fahrenwheit");
		
	}

}//Exersise2_2.java
/**
 * 程序要求:读入圆柱体的半径和高,并使用下列公式计算圆柱的体积:
 * 			面积=半径 x 半径 x π
 * 			 体积= 面积 x 高
 * 作者:wwj
 * 功能:计算圆柱体的体积
 * 
 * 运行结果:
 * Enter the radius and length of a cylinder: 5.5 12
 * The area is 95.0331
 * The volume is 1140.4
 */
import java.util.Scanner;

public class Exercise2_2 {
	public static void main(String[] args) {
		final double PI = 3.14159;
		Scanner input = new Scanner(System.in);
		
		//输入半径和高
		System.out.println("Enter the radius and length of a cylinder: ");
		double radius = input.nextDouble();
		double height = input.nextDouble();
		
		//计算面积和体积
		double area = radius * radius * PI;
		double volume = area * height;
		
		//输出结果
		System.out.println("The area is " + area);
		System.out.println("The volume is " + volume);

	}

}
//Exercise2_3.java
/**
 * 
 * 程序要求:编写程序,读入英尺数,将其转换为米数并显示结果。一英尺等于0.305米。
 * 
 * 作者:wwj
 * 日期:2012/5/8
 * 
 * 运行结果示例:
 * Enter a value for feet: 16
 * 16 feet is 4.88 meters
 */

import java.util.Scanner;

public class Exercise2_3 {
	public static void main(String[] args) {
		final double ONE_FEET = 0.305;
		Scanner input = new Scanner(System.in);
		
		//读入英尺数
		System.out.println("Enter a value for feet:");
		double feet = input.nextDouble();
		
		//转换结果
		double meter = feet * ONE_FEET;
		
		//输出
		System.out.println(feet + " feet is "+ meter + " meters ");
		
		
	}

}//Exercise2_4.java
/**
 * 
 * 程序要求:编写程序,将磅数转换为千克数。程序提示用户输入磅数,然后转换车成千克并显示结果。
 * 一磅=0.454千克。
 * 
 * 作者:wwj
 * 日期:2012/5/8
 * 
 * 运行结果示例:
 * Enter a number in pounds: 55.5
 * 55.5 pounds is 25.197 kilograms
 * 
 */

import java.util.Scanner;

public class Exercise2_4 {
	public static void main(String[]args){
		Scanner input = new Scanner(System.in);
		final double ONE_POUND = 0.454;
		
		//提示输入磅数
		System.out.println("Enter a number in pounds: ");
		double pounds = input.nextDouble();
		
		//将磅数转换为千克数
		double kilograms = pounds * ONE_POUND;
		
		//输出结果
		System.out.println(pounds + " pounds is " + kilograms + " kiligrams");
	}
}//Exercise2_5.java
/**
 * 
 * 程序要求:读入一笔费用与酬金率,计算酬金和总钱数。例如,如果用户输入10作为费用,15%作为酬金率,
 * 计算结果显示酬金$1.5,总费用$11.5.
 * 
 * 作者:wwj
 * 日期:2012/5/8
 * 功能:计算小费
 * 
 * 运行结果示例:
 * Enter the subtotal and a gratuity rate: 15.69 15
 * The gratuity is 2.35 and total is 18.04
 * 
 */

import java.util.Scanner;

public class Exercise2_5 {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		
		//读入一笔费用和酬金率
		System.out.println("Enter the subtotal and a gratuity rate: ");
		double subtotal = input.nextDouble();
		double rate = input.nextDouble() * 0.01;
		
		//计算酬金和总费用
		double gratuity = subtotal * rate;
		double totalMoney = subtotal + gratuity;
		
		//输出结果
		System.out.println("The gratuity is " + gratuity + " and total is "+ totalMoney);
		

	}

}//Exercise2_6.java
/**
 * 
 * 程序要求:读取一个在0到1000之间的整数,并将该整数的各位数字相加。
 * 例如:整数是932,各位数字之和为14。
 * 
 * 作者:wwj
 * 日期:2012/5/8
 * 功能:求一个整数各位数之和
 * 
 * 运行结果示例:
 * Enter a number between 0 and 1000:999
 * The sum of the digits is 27
 */

import java.util.Scanner;

public class Exercise2_6 {
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		int sum;
		
		//输入一个数字
		System.out.println("Enter a number between 0 and 1000: " );
		int num = input.nextInt();
		
		//分解数字 
		if(num <= 99){		
			int num1 = num % 10;
			int num2 = num / 10;
			sum = num1 + num2;
		}
		else {
			int num1 = num % 10;		//个位数
			int num2 = num % 100 / 10;	//十位数
			int num3 = num / 100;		//百位数
			sum = num1 + num2 + num3;
		}
		
		
		//输出结果
		System.out.println("The sum of the digits is " + sum);
	}

}//Exercise2_7.java
/**
 * 
 * 程序要求:编写程序,提示用户输入分钟数(例如十亿)然后显示这些分钟数代表多少年和多少天
 * 为了简化问题,假设一年又365天。
 * 
 * 作者:wwj
 * 日期:2012/5/8
 * 功能:求出年数
 * 
 * 运行结果示例:
 * Enter the number of minutes: 1000000000
 * 1000000000 minutes is approximately 1902 years and 214 days.
 */

import java.util.Scanner;

public class Exercise2_7 {
	public static void main(String[]args){
		Scanner input = new Scanner(System.in);
		final int ONEYEAR_OF_MINUTES = 365 * 60 * 24;
		final int ONEDAY_OF_MINUTES = 60 * 24;
		
		//输入分钟数
		System.out.println("Enter the number of minutes:");
		int  minutes = input.nextInt();
		
		//计算年数和天数
		int numOfYears = minutes / ONEYEAR_OF_MINUTES;
		int numOfDays = (minutes % ONEYEAR_OF_MINUTES) / ONEDAY_OF_MINUTES;
		
		//输出年数和天数
		System.out.println(minutes + " minutes is approximately " + numOfYears + " years "
				+ numOfDays + " days");
				
	}	

}//Exercise2_8.java
/**
 * 
 * 程序要求:编写程序接收一个ASCII码(从0到128的整数),然后显示它代表的字符。
 * 例如,如果用户输入的是97,程序显示的是字符a。
 * 
 * 作者:wwj
 * 日期:2012/5/8
 * 功能:求ASCII码对应的字符
 * 
 * 运行结果示例:
 * Enter an ASCII code:69
 * The character for ASCII code 69 is E
 */
import java.util.Scanner;

public class Exercise2_8 {
	public static void main(String[]args){
		Scanner input = new Scanner(System.in);
		
		
		//输入ASCII码
		System.out.println("Enter an ASCII code:");
		int ascii_code = input.nextInt();
		
		//转换为对应字符
		char character = (char)ascii_code;
		
		System.out.println("The character for ASCII code " + ascii_code + " is " + character);
		
	}

}//Exercise2_9.java
/**
 * 
 * 程序要求:改写程序清单2-10,解决将double型值为int型值时可能会造成精度损失的问题。
 * 输入的输入值是一个整数,其最后两位代表是分币值。例如:1156就表示的是11美元56美分
 * 
 * 作者:wwj
 * 日期:2012/5/8
 * 功能:整钱兑零
 */
import java.util.Scanner;

public class Exercise2_9 {
	public static void main(String[] args){
		//创建一个Scanner对象
		Scanner input = new Scanner(System.in);
		
		//输入总钱数
		System.out.print("Enter an amount,for example 1156: ");
		int amount = input.nextInt();
		
		//找出1美元的个数
		int numberOfOneDollars = amount / 100;
		amount = amount % 100;
		
		//找出2角5分币的个数
		int numberOfQuarters = amount / 25;
		amount = amount % 25;
		
		//找出1角币的个数
		int numberOfDimes = amount / 10;
		amount = amount % 10;
		
		//找出5分币的个数
		int numberOfNickles = amount /5;
		amount = amount % 5;
		
		//找出1分币的个数
		int numberOfPennies = amount;
		
		//输出结果
		System.out.println("Your amount " + amount + " consist of \n" +
				"\t" + numberOfOneDollars + " dollars\n" +
				"\t" + numberOfQuarters + " quarters\n" + 
				"\t" + numberOfDimes + " dimes\n" +
				"\t" + numberOfNickles + " nickles\n" +
				"\t" + numberOfPennies + " pennies");	
	}

}//Exercise2_10.java
/**
 * 
 * 程序要求:使用图形用户界面输入
 * 改写程序清单2-10,使用图形用户界面输出
 * 
 * 作者:wwj
 * 日期:2012/5/8
 * 功能:整钱兑换
 * 
 */

import javax.swing.JOptionPane;

public class Exercise2_10 {
	public static void main(String[] args){
		//输入总钱数
		String amountString = JOptionPane.showInputDialog(
				"Enter an amount for example 1156:");
		
		int amount = Integer.parseInt(amountString);
		
		int numberOfOneDollars = amount / 100;	//美元
		int numberOfPennies = amount % 100;	//美分
		
		String output = "Your amount " + amount + " consist of \n" + 
		"\t" + numberOfOneDollars + " dollars\n" +
		"\t" + numberOfPennies + " pennies";
		
		//输出兑零后的结果
		JOptionPane.showMessageDialog(null, output);
	}

}import javax.swing.JOptionPane;


//Exercise2_11.java
/**
 * 2.11 程序要求:编写程序,读入下列信息并打印工资单
 * 雇员的名字(例如Smith)
 * 每周的工作小时数(例如10)
 * 每小时工资(例如6.75)
 * 联邦所得税税率(例如20%)
 * 州所得税税率(例如9%)
 * 作者:wwj
 * 日期:2012/5/17
 * 功能:计算工资单
 */
public class Exercise2_11 {
	public static void main(String[] args){
		//输入对话框:雇员的名字
		String empName = JOptionPane.showInputDialog(
				"Enter employee's name,for example Smith");
		//输入对话框:每周的工作小时数
		String empHoursString = JOptionPane.showInputDialog(
				"Enter number of hours worked in a week:");
		//将string类型的工作小时数转换为double类型
		double empHours = Double.parseDouble(empHoursString);
		//输入对话框:每小时工资
		String empHourSalaryString = JOptionPane.showInputDialog(
				"Enter hourly pay rate:");
		//将string类型的工资转换为double类型
		double empHourSalary = Double.parseDouble(empHourSalaryString);
		//输入对话框:联邦所得税税率
		String fedaralRateString = JOptionPane.showInputDialog(
				"Enter federal tax withholding rate:");
		//将string类型税率转换为double类型
		double federalRate = Double.parseDouble(fedaralRateString);
		//输入对话框:州所得税税率
		String stateRateString = JOptionPane.showInputDialog(
				"Enter state tax withholding rate:");
		double stateRate = Double.parseDouble(stateRateString);
		double grossPay = empHourSalary * empHours;
		double federalRatePay = grossPay * federalRate;
		double stateRatePay = grossPay * stateRate;
		double totalDeduction = federalRatePay + stateRatePay;
		//打印结果
		String output  = "Employee Name: " + empName +
						"\nHour Worked: " + empHours + 
						"\nPay Rate: " + empHourSalary + 
						"\nGross Pay: " + grossPay +
						"\nDeductions:\n" + 
						"  Federal Withholding(" + federalRate + "):"+ federalRatePay+ 
						"\n State Withholding(" + stateRate + "):"+ stateRatePay +
						"\n Total Deduction" + totalDeduction + "";
		JOptionPane.showMessageDialog(null, output);
		
		
	}

}import java.util.Scanner;

/**
 * 2.12 程序要求:如果你知道收支余额和年利率的百分比,你就可以是使用下面的公式计算下个月要支付的利息额:
 * 利息额=收支余额 x (年利率/1200)
 * @author wwj
 *
 */
public class Exercise2_12 {
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		
		//请输入收支余额和年利率
		System.out.println("Enter balance and interest rate(e.g., 3 for 3%):" );
		double balance = input.nextDouble();
		double interestRate = input.nextDouble();
		
		//计算下个月要支付的利息额
		double interest = balance * (interestRate / 1200);
		
		//输出结果
		System.out.println("The interest is:" + interest);
	
		
	}

}import java.util.Scanner;

/**
 * 2.13 程序要求:编写程序,读取投资总额、年利率和年数,然后使用下面的公式显示未来的投资金额:
 * futureInvestmentValue = investmentAmount * (1 + annuallyInterestRate)^(numberOfYears*12)
 * @author wwj
 *
 */
public class Exercise2_13 {
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		
		//读取投资总额
		System.out.print("Enter investment amount:");
		int investment = input.nextInt();
		//读取年利率
		System.out.print("Enter monthly interest rate:");
		double rate = input.nextDouble();
		//读取年数
		System.out.print("Enter number of years:");
		int years = input.nextInt();
		
		//计算未来的投资金额
		double futureInvestmentValue = investment * Math.pow(1 + rate, years * 12);
		
		//显示结果
		System.out.println("Accumulated value is:" + futureInvestmentValue);
		
		
	}
import java.util.Scanner;

/**
 * 2.13 程序要求:编写程序,读取投资总额、年利率和年数,然后使用下面的公式显示未来的投资金额:
 * futureInvestmentValue = investmentAmount * (1 + annuallyInterestRate)^(numberOfYears*12)
 * @author wwj
 *
 */
public class Exercise2_13 {
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		
		//读取投资总额
		System.out.print("Enter investment amount:");
		int investment = input.nextInt();
		//读取年利率
		System.out.print("Enter monthly interest rate:");
		double rate = input.nextDouble();
		//读取年数
		System.out.print("Enter number of years:");
		int years = input.nextInt();
		
		//计算未来的投资金额
		double futureInvestmentValue = investment * Math.pow(1 + rate, years * 12);
		
		//显示结果
		System.out.println("Accumulated value is:" + futureInvestmentValue);
		
		
	}
import java.util.Scanner;
/**
 * 2.14 程序要求:计算BMI(身体质量指数),它的值可以通过将体重(以公斤为单位)除以身高(以米为单位)
 * 的平方值得到。编写程序,提示用户输入体重(以磅为单位)以及身高(以米为单位),然后显示BMI
 * @author Administrator
 *
 */

public class Exercise2_14 {
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		
		//输入体重
		System.out.print("Enter weight in pounds :");
		double weight = input.nextDouble() * 0.45359237;
		//输入身高
		System.out.print("Enter height in inches :");
		double height = input.nextInt() * 0.0254;
		
		//计算BMI
		double BMI = weight / Math.pow(height, 2);
		
		//显示BMI
		System.out.println("BMI is:" + BMI);
	}

}
import java.util.Scanner;

/**
 * 2.15 程序要求:假设你每月向银行账户存100美元,年利率为5%,那么每月利率是0.05/12=0.00417.
 * 第一个月之后,账户上的值就变成:100 * (1 + 0.00417) = 100.417
 * 第二个月之后,账户上的值就变成:(100 + 100.417) * (1+ 0.00417) = 201.252
 * 第三个月之后,账户上的值就变成:(100 + 201.252) * (1+ 0.00417) = 302.507
 * 依此类推。
 * 编写程序显示六个月之后账户上的钱数。
 * @author wwj
 *
 */
public class Exercise2_15 {
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		
		int annuallyMonthDollar = 100;
		double interestRate = 0.05 / 12.0;
		
		//1~6月份账户的值
		double firstMonthAcount = annuallyMonthDollar * (1 + interestRate);
		double secondMonthAcount = (annuallyMonthDollar + firstMonthAcount) * (1 + interestRate);
		double thirdMonthAcount = (annuallyMonthDollar + secondMonthAcount) * (1 + interestRate);
		double forthMonthAcount = (annuallyMonthDollar + thirdMonthAcount) * (1 + interestRate);
		double fifthMonthAcount = (annuallyMonthDollar + forthMonthAcount) * (1 + interestRate);
		double sixthMonthAcount = (annuallyMonthDollar + fifthMonthAcount) * (1 + interestRate);
		
		//显示六月后账户的值
		System.out.println("sixthMonthAcount is " + sixthMonthAcount);
		
	}

}import java.util.Scanner;

/**
 * 2.16 程序要求:编写程序,计算将水从初始温度加热到最终温度所需的能量。
 * 计算能量的公式是:
 * 			Q = M * (最终温度 - 初始温度) * 4184
 * 这里的M是千克为单位的水的重量,温度以摄氏度为单位,而能量Q以焦耳为单位。
 * @author wwj
 *
 */
public class Exercise2_16 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner input = new Scanner(System.in);
		
		//输入水的重量
		System.out.print("Enter the amount of water in kilograms:");
		double M = input.nextDouble();
		//输入初始温度
		System.out.print("Enter the initial temperature:");
		double initialTemp = input.nextDouble();
		//输入最终温度
		System.out.print("Enter the final temperature:");
		double finalTemp = input.nextDouble();
		
		double Q = M * (finalTemp - initialTemp) * 4184;
		System.out.println("The energy needed is :" + Q);
		
	}

}import java.util.Scanner;

/**
 * 2.17 程序要求:计算风寒温度,计算公式如下:
 * t=35.74 + 0.6215 * t' - 35.75 * v^0.16 + 0.4275 * t' * v^0.16
 * 这里的t’是室外温度,以华摄氏度为单位,而v是速度,以每小时英里数为单位。t是风寒温度。
 * 该公式不适用于风速低于2mph或温度在-58F以下或41F以上的情况。
 * @author wwj
 *
 */
public class Exercise2_17 {
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		
		//输入室外的温度
		System.out.print("Enter the temperature in Fahrenheit: ");
		double temp = input.nextDouble();
		//输入风速
		System.out.print("Enter the wind speed miles per hours: ");
		double wSpeed = input.nextDouble();
		
		//计算风寒温度
		double t = 35.74 + 0.6215 * temp - 35.75 * Math.pow(wSpeed, 0.16) + 0.4275 * temp * Math.pow(wSpeed, 0.16);
		
		//显示结果
		System.out.println("The wind chill index is " + t);
	}
			
}/**
 * 2.18 程序要求:打印表格,显示下面的表格:
 * a	b	pow(a,b)
 * 1	2	1
 * 2	3	8
 * 3	4	81
 * 4	5	1024
 * 5	6	15625
 * @author wwj
 *
 */
public class Exercise2_18 {
	public static void main(String[] args){
		int a,b;
		int n = 5;
		System.out.println("a     b     pow(a,b)");
		for (int i = 1; i <= n; i++){
			a = i;
			b = i + 1;
			System.out.println(a + "     " + b + "     " + Math.pow(a,b));
		}
	}

}/**
 * 2.19 编写程序,使用System.CurrentTimeMillis()显示任意一个大写字母
 * @author wwj
 *
 */
public class Exercise2_19 {
	public static void main(String[] args){
		long time = System.currentTimeMillis();
		int num = (int)(time % 25) + 65;
		System.out.println((char)num);
		
	}

}import java.util.Scanner;

/**
 * 2.20 程序要求:编写程序,提示用户输入两个点(x1,y1)和(x2,y2)然后显示两点间的距离。
 * 计算两点间距离的公式是sqrt(Math.pow(x2-x1,2)+Math.pow(y2-y2,2)).
 * @author Administrator
 *
 */
public class Exercise2_20 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner input = new Scanner(System.in);
		
		//输入第一个点
		System.out.println("Enter x1 and y1:");
		double x1,y1;
		x1 = input.nextDouble();
		y1 = input.nextDouble();
		//输入第二个点
		System.out.println("Enter x2 and y2");
		double x2,y2;
		x2 = input.nextDouble();
		y2 = input.nextDouble();
		
		//计算两点间距离
		double distance = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));
		//显示结果
		System.out.println("The distance of the two points is:" + distance);

	}

}import java.util.Scanner;

/**
 * 2.21 程序要求:编写程序,提示用户输入三角形的三个点(x1,y1)、(x2,y2)、(x3,y3)
 * 然后显示它的面积。计算三角形面积的公式是:
 * s = (side1 + side2 + side3)/2
 * area= sqrt(s(s-side1)(s-side2)(s-side3))
 * @author Administrator
 *
 */
public class Enxecise2_21 {
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);
		
		//输入三个点
		System.out.print("Enter three points for a triangle:");
		double x1,x2,x3,y1,y2,y3;
		x1 = input.nextDouble();
		y1 = input.nextDouble();
		x2 = input.nextDouble();
		y2 = input.nextDouble();
		x3 = input.nextDouble();
		y3 = input.nextDouble();
		
		//计算三角形面积
		double side1 = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));
		double side2 = Math.sqrt(Math.pow(x3 - x2, 2) + Math.pow(y3 - y2, 2));
		double side3 = Math.sqrt(Math.pow(x1 - x3, 2) + Math.pow(y1 - y3,2));
		double s = (side1 + side2 + side3) / 2;
		double area = Math.sqrt(s * (s - side1) * (s - side2) * (s - side3) );
		
		//显示结果
		System.out.println("The area of the triangle is :" + area);
	}

}import java.util.Scanner;

/**
 * 2.22 程序要求:编写程序,提示用户输入六边形的边长,然后显示它的面积。
 * 计算六边形面积的公式:
 * area =( 3 * sqrt(3) * s^2 )/ 2
 * @author Administrator
 *
 */
public class Exercise2_22 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner input = new Scanner(System.in);
		
		//输入六边形的边长
		System.out.print("Enter the side:" );
		double side = input.nextDouble();
		
		//计算面积
		double area =( 3 * Math.sqrt(3) * side * side)/2;
		
		//显示结果
		System.out.println("The area of the hexagon " + area);

	}

}import java.util.Scanner;

/**
 * 2.23 程序要求:平均加速度定义为速度的变化量除以这个变化所用的时间,如下式:
 * a = (v1 - v0) / t
 * @author wwj
 *
 */
public class Exercise2_23 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner input = new Scanner(System.in);
		
		//输入起始速度、终止速度、时间段
		System.out.print("Enter v0,v1,and t:");
		double v0 = input.nextDouble();
		double v1 = input.nextDouble();
		double t = input.nextDouble();
		
		//计算加速度
		double a = (v1 - v0) / t;
		
		//显示加速度
		System.out.println("The average acceleration is :" + a);
	}

}import java.util.Scanner;

/**
 * 2.24 程序要求:假设一个飞机的加速度是a而起飞速度是v,那么飞机起飞所需要的最短跑道长度
 * length = v^2 / 2*a
 * 编写程序,提示用户输入以米/秒为单位的速度v和以米/秒的平方为单位的加速度a,然后显示最短跑道长度
 * @author wwj
 *
 */
public class Exercise2_24 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner input = new Scanner(System.in);
		
		//输入v和a
		System.out.print("Enter v and a:");
		double v = input.nextDouble();
		double a = input.nextDouble();
		//计算跑道长度
		double length = Math.pow(v,2)/( 2 * a);
		
		//显示结果
		System.out.println("The minimum runway length for this airplaneis :" + length);
	}

}