Java 韩元'；t从布尔表达式中调用变量

我很难找到java在调用变量时遇到的问题。我正在创建一个简单的聊天机器人，这就是我目前所拥有的：

public class Chatbot {
    public static void main(String[] args) {
        String name = JOptionPane.showInputDialog("Hi! How are you? My name is Chatbot! What is yours? ");
        if (name.compareTo("a")<0){
            String city = JOptionPane.showInputDialog("Nice to meet you! Where are you from, "+name);
        }
        else
        {
            String city = JOptionPane.showInputDialog("Huh. That's a strange name. Where are you from,"+name);  
        }


        if (!city.equals("Seattle")){

        }

    }
}

公共类聊天机器人{
公共静态void main（字符串[]args）{
String name=JOptionPane.showInputDialog（“嗨！你好吗？我叫Chatbot！你的名字是什么？”）；
if（name.compareTo（“a”）当前
city
的作用域仅限于if或else块。通过在方法级别声明使其成为局部变量来增加其作用域

公共静态void main（字符串[]args）{

String name=JOptionPane.showInputDialog（“嗨！你好吗？我的名字是Chatbot！你的名字是什么？”）；
字符串城市=”；
if（name.compareTo（“a”）顶部的贴花
字符串city=null
。然后使用它。它必须在
if-else
块之外

String city=null;
    String name = JOptionPane.showInputDialog("Hi! How are you? My name is Chatbot! What is yours? ");
if (name.compareTo("a")<0){
            city = JOptionPane.showInputDialog("Nice to meet you! Where are you from, "+name);
        }
        else
        {
            city = JOptionPane.showInputDialog("Huh. That's a strange name. Where are you from,"+name);  
        }

String city=null；
String name=JOptionPane.showInputDialog（“嗨！你好吗？我叫Chatbot！你的名字是什么？”）；
if（name.compareTo（“a”）如前所述，您需要在if-else块之外声明城市，如下所示：

public static void main(String[] args) {
    String name = JOptionPane.showInputDialog("Hi! How are you? My name is Chatbot! What is yours?");
    String city = null;
    if (name.compareTo("a")<0){
       city = JOptionPane.showInputDialog("Nice to meet you! Where are you from, "+name);
    }
        else
    {
        city = JOptionPane.showInputDialog("Huh. That's a strange name. Where are you from,"+name);  
    }
    if (!city.equals("Seattle")){

    }

}

publicstaticvoidmain（字符串[]args）{
String name=JOptionPane.showInputDialog（“嗨！你好吗？我叫Chatbot！你的名字是什么？”）；
字符串city=null；
如果（name.compareTo（“a”）尝试以下操作，希望对您有所帮助

 public static void main( String[] args )
        {

            String name = JOptionPane.showInputDialog( "Hi! How are you? My name is Chatbot! What is yours? " );
            String city = "";
            if ( name.compareTo( "a" ) < 0 )
            {

                city = JOptionPane.showInputDialog( "Nice to meet you! Where are you from, " + name );
            }
            else
            {
                city = JOptionPane.showInputDialog( "Huh. That's a strange name. Where are you from," + name );
            }

            if ( !city.equals( "Seattle" ) )
            {

            }

        }

publicstaticvoidmain（字符串[]args）
{
String name=JOptionPane.showInputDialog（“嗨！你好吗？我叫Chatbot！你的名字是什么？”）；
字符串城市=”；
如果（名称比较（“a”）<0）
{
city=JOptionPane.showInputDialog（“很高兴认识你！你从哪里来，”+name）；
}
其他的
{
city=JOptionPane.showInputDialog（“哈，这是个奇怪的名字，你从哪里来，”+name）；
}
如果（！city.equals（“西雅图”））
{
}
}
在条件之前声明city。变量
city
仅对if-else块是局部的。向下滚动到“Loop Scope”上读，因为Java使用块作用域。它不需要是全局的，只是局部性比它们小一点（实际上有两个不同的变量称为city，一个在
if
中，另一个在
else
中）当前为。
 public static void main( String[] args )
        {

            String name = JOptionPane.showInputDialog( "Hi! How are you? My name is Chatbot! What is yours? " );
            String city = "";
            if ( name.compareTo( "a" ) < 0 )
            {

                city = JOptionPane.showInputDialog( "Nice to meet you! Where are you from, " + name );
            }
            else
            {
                city = JOptionPane.showInputDialog( "Huh. That's a strange name. Where are you from," + name );
            }

            if ( !city.equals( "Seattle" ) )
            {

            }

        }