Question

我一直在为一个小程序编写代码，但我收到了这个错误：

Compilation error   time: 0.11 memory: 380672 signal:0Main.java:22: 
error: cannot find symbol
            string dtext = "One";
        ^
  symbol:   class string
  location: class Ideone
Main.java:37: error: cannot find symbol
        System.out.println(dtext);
                       ^
  symbol:   variable dtext
  location: class Ideone
2 errors

我的代码：

import java.util.*;
import java.lang.*;
import java.io.*;
import static java.lang.System.*;
import java.util.Scanner;
import java.lang.String;

class Ideone
{
public static void main (String str[]) throws IOException
{
    Scanner sc = new Scanner(System.in);

    //System.out.println("Please enter the month of birth");
    //int month = sc.nextInt();
    System.out.println("Please enter the day of birth");
    int day = sc.nextInt();

    //day num to day text
    if (day == 1)
    {
        string dtext = "One";
    }
    else if (day == 2)
    {
        string dtext = "Two";
    }
    else if (day == 3)
    {
        string dtext = "Three";
    }
    else
    {
        System.out.println("Error, day incorrect.");
    }

    System.out.println(dtext);
}
}

我做了一些研究，发现java找不到字符串变量，但为什么呢？定义了变量，并且print语句是正确的。

Answer 1

java中没有string类。有String类。

string dtext = "Two";

应该是

   String dtext = "Two";

S必须是资本。

查看您的String variable范围。您被限制为block。将其移至顶部，

然后您的代码看起来像

String dtext = "";
        if (day == 1) {
            dtext = "One";
        } else if (day == 2) {
            dtext = "Two";
        } else if (day == 3) {
            dtext = "Three";
        } else {
            System.out.println("Error, day incorrect.");
        }
        System.out.println(dtext);

Answer 2

你有拼写错误

String dtext = "One";

查看String class

还有一件事要检查variable scope

if (day == 1)
{
    String dtext = "One";  //it dtext has local scope here
}//after this line dtext is not available

在dtext之外声明if为

String dtext = "";
 if (day == 1)
 {
    dtext = "One";
 }
 else if (day == 2)
 {
    dtext = "Two";
 }
 else if (day == 3)
 {
    dtext = "Three";
 }
 else
 {
    System.out.println("Error, day incorrect.");
 }

System.out.println(dtext);

Answer 3

java中不存在

字符串。您的string首字母应为首字母 - ＆gt; String

例如

将string dtext = "One";更改为String dtext = "One";

从您的代码中

if (day == 1)
{
    string dtext = "One";
}
else if (day == 2)
{
    string dtext = "Two";
}
else if (day == 3)
{
    string dtext = "Three";
}
else
{
    System.out.println("Error, day incorrect.");
}

System.out.println(dtext);      //this line will get error dtext variable in not reachable.

您的代码需要如下所示

String dtext ="";
if (day == 1)
{
    dtext = "One";
}
else if (day == 2)
{
    dtext = "Two";
}
else if (day == 3)
{
    dtext = "Three";
}
else
{
    System.out.println("Error, day incorrect.");
}
System.out.println(dtext);

如果语句错误，找不到符号

3 个答案: