What does "*&" mean in C + + function parameters? ”

typedef struct BITNODE
{
char value;
Bitnode *lchild,*rchild;
}bitnode,*bitree;

void Creattree (bitnode* &root,char *pre,int l1,int r1,char *in,int l2,int R2);

/* What does *& stand for? Https://zhidao.baidu.com/question/2266744263935050308.html

This is the syntax for C + +,& The reference argument in the formal parameter,
Lnode * &LST; The Lnode * is a whole, indicating that the variable type is a Lnode class pointer, and the & in &lst indicates the reference argument, which is an alias representing the argument.
Standard C does not support this notation.

Ask

& not address characters? What does the reference parameter mean?

Chase Answer

& in the variable definition area, indicating the reference, pay attention to its usage,
& in the variable operation area, which represents the fetch address character, such as:

int x=10, *p=&x; Here & function on X, is to take the address character
int &x; Reference is a new feature introduced by C + +, you do not want to learn C + +, the above code you do not understand. The & Here is quoted. In general, this form will appear in the formal parameter.

Lnode * &LST; The Lnode * is a whole, indicating that the variable type is a Lnode class pointer, and the & in &lst indicates the reference argument, which is an alias representing the argument. Manipulating reference variables is equivalent to manipulating real parametric



*/

Binary tree using pre-order and middle order (source code):

2. #include <iostream>
4. #include <cstdio>
6. #include <cstdlib>
8. #include <cstring>
10. using namespace std;;
14. const int n=;
22. typedef struct bitnode
24. {
26. char value;
28. Bitnode *lchild,*rchild;
30. }bitnode,*bitree;
34. / * What does *& stand for?
38. This is the syntax for C + +,& The reference argument in the formal parameter,
40. Lnode * &LST; Lnode * is a whole, indicating that the variable type is a Lnode class pointer, and that the & in &lst indicates the reference argument, which is an alias representing the argument.
42. standard C does not support this notation.
46. questioning
50. & not address characters? What does the reference parameter mean?
54. Chase Answer
58. & in the variable definition area, indicating the reference, pay attention to its usage,
60. & in the variable operation area, which represents the fetch address character, such as:
64. int x=10, *p=&x;//here & function on X, is take address character
66. int &x;//reference is a new feature introduced by C + +, you do not learn C + +, the above code you do not understand. The & Here is quoted. In general, this form will appear in the formal parameter.
70. Lnode * &LST; Lnode * is a whole, indicating that the variable type is a Lnode class pointer, and that the & in &lst indicates the reference argument, which is an alias representing the argument. Manipulating reference variables is equivalent to manipulating real parametric
78. */
82. void creattree(bitnode* &root,char *pre,int L1,int R1,char *in,int L2, int R2)
84. {
86. if (L1<=R1&&L2<=R2)
88. {
90. int KEY=PRE[L1];
92. int midindex=-1;
94. For (int i=l2;i<=r2;i++)
96. {
98. if (in[i]==key)
100. {
102. Midindex=i;
104. Break ;
106. }
108. }
110. root= (Bitnode *)malloc (sizeof (Bitnode));
112. root->value=key;
114. root->lchild=NULL;
116. root->rchild=NULL;
118. int llen=midindex-l2;
120. Creattree (Root->lchild, Pre, l1+1, L1+llen, in, L2, Midindex-1);
122. Creattree (Root->rchild, Pre, l1+llen+1, R1, in, midindex+1, r2);
124. }
126. }
130. void postordertraverse(bitnode *&root)
132. {
134. if (root->lchild)
136. Postordertraverse (Root->lchild);
138. if (root->rchild)
140. Postordertraverse (Root->rchild);
142. printf ("%c", Root->value);
144. }
148. int main()
150. {
152. Char pre[n],in[n];
154. while (scanf ("%s", pre)!=eof)
156. {
158. scanf ("%s", in);
160. int len1=strlen (pre);
162. int len2=strlen (in);
164. Bitnode *root=NULL;
166. Creattree (Root,pre,0,len1-1,in,0,len2-1);
168. Postordertraverse (root);
170. printf ("\ n");
172. }
174. return 0;
176. }

What does "*&" mean in C + + function parameters? ”