整个程序应该输入一个组合锁并接受这个组合。这是我遇到问题的代码。

import java.util.*;  // needed for Scanner

public class CombinationLock extends Lock
{
   // Instance Variables
   private String combination;

   Scanner keyboard = new Scanner(System.in);

   System.out.println("Enter Combination --> ");
   String combo = keyboard.nextLine();

   if(combination = combo)
   {
    super.open();
   }

public String toString()
   {
    String str = super.toString() + "\n" +
                 "Combination = " + combination + "\n";  
    return str;
   }

public void setCombination()
{

}

public boolean getCombination()
{

}

public CombinationLock()
{
   super();    // call the default constructor of the Lock class
   combination = "";
}

public CombinationLock(String combo)
{
    super();
    combination = combo;
}

}

这些就是我犯的错误

--------------------Configuration: <Default>--------------------
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:10: error: <identifier> expected
   System.out.println("Enter Combination  ");
                     ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:10: error: illegal start of type
   System.out.println("Enter Combination  ");
                      ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:13: error: illegal start of type
   if(combination = combo)
   ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:13: error: <identifier> expected
   if(combination = combo)
                 ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:13: error: ';' expected
   if(combination = combo)
                   ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:13: error: illegal start of type
   if(combination = combo)
                         ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:13: error: <identifier> expected
   if(combination = combo)
                          ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:14: error: ';' expected
   {
    ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:15: error: illegal start of type
    super.open();
         ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:18: error: class, interface, or enum expected
public String toString()
       ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:22: error: class, interface, or enum expected
    return str;
    ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:23: error: class, interface, or enum expected
   }
   ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:25: error: class, interface, or enum expected
public void setCombination()
       ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:30: error: class, interface, or enum expected
public boolean getCombination()
       ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:35: error: class, interface, or enum expected
public CombinationLock()
       ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:38: error: class, interface, or enum expected
   combination = "";
   ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:39: error: class, interface, or enum expected
}
^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:41: error: class, interface, or enum expected
public CombinationLock(String combo)
       ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:44: error: class, interface, or enum expected
    combination = combo;
    ^
C:\Users\waki_\OneDrive\Documents\CombinationLock.java:45: error: class, interface, or enum expected
}
^
20 errors

Process completed.

我不确定是什么导致了这个问题。我试图找到其他的答案，但都与我的问题无关。