你好我正在为我的计算机科学课写一个程序。目标是制作一个计算毕达哥拉斯定理的计算器。我已经做了一些关于我需要用来循环的研究。喜欢while和do-while语句，但我无法弄清楚如何实现它们。我已经尝试了，并且有一些证据表明我的代码在我的代码中被注释掉了。我该如何制作循环？
我的代码：
import java.util.Scanner;
public class Pythagorean_Theorem
{
public static void main(String[] args)
{
// established scanner
Scanner Toby = new Scanner (System.in);
// Declares variables
double Leg1;
double Leg2;
double Hypotenuse;
double choice;
//double num1
//double num2
//double answer
//boolean False;
// Beginning of program offering choice for calculations
System.out.println ("This program is a basic calculator that also knows the Pythagorean theorem");
System.out.println ("This program can solve for the hypotenuse or one of the legs \nOr you can use it as a simple calculator");
System.out.println ("Are you solving for the hypotenuse or a leg?");
System.out.println ("1 for hypotenuse \n2 for leg");
choice = Toby.nextDouble();
//Begins else if statements
//What you enter above corresponds to the choices below
//while ((Toby.nextDouble() != 1);
//while ((Toby.nextDouble() != 2);
{
if (choice == 1)
{
// Finding hypotenuse
System.out.println ("Enter first leg:");
Leg1 = Toby.nextDouble();
System.out.println ("Enter second leg:");
Leg2 = Toby.nextDouble();
Hypotenuse = Leg1 * Leg1 + Leg2 * Leg2;
System.out.println (Math.sqrt(Hypotenuse));
}
else if (choice == 2)
{
// Finding leg
System.out.println ("Enter the leg:");
Leg1 = Toby.nextDouble();
System.out.println ("Enter hypotenuse");
Hypotenuse = Toby.nextDouble();
Leg2 = (Hypotenuse * Hypotenuse - Leg1 * Leg1);
System.out.println (Math.sqrt(Leg2));
}
// Below here is invalid choices
else if (choice <= 0)
{
System.out.println ("This is not a valid choice");
}
else if (choice >= 3)
{
System.out.println ("This is not a valid choice");
}
}
}
}
答案 0 :(得分：0)
有很多方法可以做到这一点。一个简单的模式是使用布尔值，如
boolean worked = false;
do {
//try to get valid input
//if input is valid and calculation is done, worked = true
} while (!worked);
另一种方法是使用例外。如果您了解异常，这是我推荐的更先进的技术，但是由于您对如何使用循环的困惑，我猜您还没达到这个
答案 1 :(得分：0)
import java.util.Scanner;
public class Pythagorean_Theorem{
public static void main(String[] args){
//...
boolean exit = false;
do {
// Beginning of program offering choice for calculations
System.out.println ("This program is a basic calculator that also knows the Pythagorean theorem");
//...
System.out.println ("1 for hypotenuse \n2 for leg \n3 for exit");
choice = Toby.nextDouble();
//...
if (choice == 1){
// ...
} else if (choice == 2) {
// ...
} else if (choice == 3) {
exit = true;
System.out.println ("Bye!");
} else {
System.out.println ("This is not a valid choice");
}
} while (!exit);
}
}
答案 2 :(得分：0)
package test.com;
import java.io.File;
import java.io.IOException;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.io.StringWriter;
import java.net.InetAddress;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import org.apache.commons.net.ntp.NTPUDPClient;
import org.apache.commons.net.ntp.TimeInfo;
class Employee {
public int id;
private double balance;
public Employee(int id) {
// TODO Auto-generated constructor stub
this.id = id;
}
public boolean charge(double price){
if (price + balance > 1)
return false;
balance += price;
return true;
}
}
class B extends Employee {
public B(int id) {
super(id);
// TODO Auto-generated constructor stub
}
public boolean charge(double price){
boolean isSuccess = super.charge(price);
if(!isSuccess)
super.charge(5); //*** here the penalty
return isSuccess;
}
}
public class TestStrig {
public static void main(String[] args) throws Exception {
// established scanner
Scanner Toby = new Scanner (System.in);
// Declares variables
double Leg1;
double Leg2;
double Hypotenuse;
double choice;
//double num1
//double num2
//double answer
//boolean False;
// Beginning of program offering choice for calculations
while(true) {
System.out.println ("This program is a basic calculator that also knows the Pythagorean theorem");
System.out.println ("This program can solve for the hypotenuse or one of the legs \nOr you can use it as a simple calculator");
System.out.println ("Are you solving for the hypotenuse or a leg?");
System.out.println ("1 for hypotenuse \n2 for leg \n3 to Exit");
choice = Toby.nextDouble();
//Begins else if statements
//What you enter above corresponds to the choices below
//while ((Toby.nextDouble() != 1);
while (true) {
if (choice == 1)
{
// Finding hypotenuse
System.out.println ("Enter first leg:");
Leg1 = Toby.nextDouble();
System.out.println ("Enter second leg:");
Leg2 = Toby.nextDouble();
Hypotenuse = Leg1 * Leg1 + Leg2 * Leg2;
System.out.println (Math.sqrt(Hypotenuse));
break;
}
else if (choice == 2)
{
// Finding leg
System.out.println ("Enter the leg:");
Leg1 = Toby.nextDouble();
System.out.println ("Enter hypotenuse");
Hypotenuse = Toby.nextDouble();
Leg2 = (Hypotenuse * Hypotenuse - Leg1 * Leg1);
System.out.println (Math.sqrt(Leg2));
break;
}
// Below here is invalid choices
else if (choice == 3) {
System.out.println("Bye Bye");
System.exit(0);
}
else if (choice >= 4 || choice <= 0)
{
System.out.println ("This is not a valid choice");
break;
}
}
}
}
}
答案 3 :(得分：-1)
do {
choice = toby.nextDouble()
check the choice is your expected output or not using if..else condition
and use an choice to exit
}while(condition)
还可以使用try catch语句来捕获相应的异常并继续循环以实现您的功能。