class TreeNode {
public int val;
public TreeNode left;
public TreeNode right;
public TreeNode() {
}
public TreeNode(int val) {
this.val = val;
}
}
public class Solution {
public static void main(String[] args) {
TreeNode t1 = null;
change(t1);
System.out.println(t1==null?null:t1.val);
TreeNode t2 = new TreeNode(100);
Change(t2);
System.out.println(t2.val);
}
//无论传递的参数是否是null,都无法在函数内部改变引用变量的指向!
public static void change(TreeNode t1){
t1 = new TreeNode(100);
}
public static void Change(TreeNode t2){
t1 = new TreeNode(200);
}
}