Java if-else條件語法錯誤？

Question

我想運行下面的程序，但得到一些錯誤。有人可以幫助我，瞭解條件陳述的錯誤嗎？

import java.util.Scanner; 


public class separatingFirstCharacters { 

    public static void main(String[] args) { 
    Scanner reader = new Scanner(System.in); 

     System.out.println("Type your name: "); 
     String name = reader.nextLine(); 


     If (name.length()>3) { 
      char firstcharacter =name.charAt(0); 
      System.out.println ("First character : " + firstcharacter); 
      char secondcharacter = name.charAt(1); 
      System.out.println ("Second character : " + secondcharacter); 
      char thirdcharacter=name.charAt(3); 
      System.out.println("Third character: "+thirdcharacter); 
      } 
      else 
      { 
       System.out.println("name : " + name); 
      } 
     }  
    } 

控制檯錯誤：

Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
    The method If(boolean) is undefined for the type separatingFirstCharacters 
    Syntax error, insert ";" to complete Statement 
    Syntax error on token "else", delete this token 

    at separatingFirstCharacters.main(separatingFirstCharacters.java:13) 

Answer 1

你有1級編譯的問題（ '如果' 應該是 '如果'），並與第三字符是第四（name.charAt（3）應name.charAt（2））的另一個問題：

import java.util.Scanner; 

public class separatingFirstCharacters { 

    public static void main(String[] args) { 
     Scanner reader = new Scanner(System.in); 

     System.out.println("Type your name: "); 
     String name = reader.nextLine(); 

     if (name.length() > 3) { 
      char firstcharacter = name.charAt(0); 
      System.out.println("First character : " + firstcharacter); 
      char secondcharacter = name.charAt(1); 
      System.out.println("Second character : " + secondcharacter); 
      char thirdcharacter = name.charAt(2); 
      System.out.println("Third character: " + thirdcharacter); 
     } else { 
      System.out.println("name : " + name); 
     } 
    } 
} 

Answer 2

Java是區分大小寫的語言，if意味着小寫。

Answer 3

所有Java基本語法區分大小寫和小寫

如果（name.length（）> 3）

Answer 4

管線

如果（name.length（）> 3）{

更改爲 如果（name.length（）> 3）{

請注意，如果應小寫

Answer 5

寫入請更正他語法... 它應該是：

if (name.length()>3) { 
    char firstcharacter =name.charAt(0); 
    System.out.println ("First character : " + firstcharacter); 
    char secondcharacter = name.charAt(1); 
    System.out.println ("Second character : " + secondcharacter); 
    char thirdcharacter=name.charAt(3); 
    System.out.println("Third character: "+thirdcharacter); 
    } 
    else 
     { 
     System.out.println("name : " + name); 
     } 
    }