我一直在这一点工作,它不会编译。它给了我一个错误说使用开关并尝试声明来验证用户输入
变量的选择可能没有 初始化 开关(选择) ^
,但我在程序变量集。所以我不知道问题是什么?它是否真的能够避免编译?
import java.io.*;
import javax.swing.JOptionPane;
public class MyType
{
public static void main(String[] args)
{
String strChoice = "", strTryString, strTryInt, strTryDouble;
Integer choice, tryInt;
double tryDouble;
boolean done = false;
while(!done)
{
try
{
String answer = JOptionPane.showInputDialog(null, "What's my type\n\n\n1) String\n2) integer\n3) double\n4) Quit the program");
choice = Integer.parseInt(strChoice);
//test for valid codes 1, 2, 3, or 4
if (choice<1 || choice>4) throw new NumberFormatException();
else done = true;
}
catch(NumberFormatException e)
{
JOptionPane.showInputDialog(null, "Please enter a 1, 2, 3, or 4", "Error", JOptionPane.INFORMATION_MESSAGE);
switch(choice)
{
case 1:
JOptionPane.showMessageDialog(null, "Correct, any input can be saved as a String");
break;
case 2:
JOptionPane.showMessageDialog(null, "Correct!");
tryInt = Integer.parseInt(strChoice);
break;
case 3:
JOptionPane.showMessageDialog(null, "Correct!");
tryDouble = Integer.parseInt(strChoice);
break;
case 4:
done = true;
JOptionPane.showMessageDialog(null, "Exit.");
System.exit(0);
break;
default: throw new NumberFormatException();
}
}
}
}
}
仅供参考'Java',而不是'JAVA' :) – 2011-03-28 19:22:03