这是我在 vi 中的示例文件
1./*
2. * C Program to Build Binary Tree if Inorder or Postorder Traversal as Input
3. *
4. * 40
5. * / \
6. * 20 60
7. * / \ \
8. * 10 30 80
9. * \
10. * 90
11. * (Given Binary Search Tree)
12. */
13.#include <stdio.h>
14.#include <stdlib.h>
15.
16.struct btnode
17.{
18. int value;
19. struct btnode *l;
20. struct btnode *r;
21.}*root = NULL, *temp = NULL;
22.
23.typedef struct btnode N;
24.void insert();
25.N* bt(int arr[],int,int);
26.N* new(int);
27.void inorder(N *t);
28.void create();
29.void search(N *t);
30.void preorder(N *t);
31.void postorder(N *t);
32.
33.void main()
34.{
35. int ch, i, n;
36. int arr[] = {10, 20, 30, 40, 60, 80, 90};
37. n = sizeof(arr) / sizeof(arr[0]);
38.
39. printf("\n1- Inorder\n");
40. printf("2 - postorder\n");
41. printf("\nEnter choice : ");
42. scanf("%d", &ch);
43. switch (ch)
44. {
45. case 1:
46. root = bt(arr, 0, n-1);
47. printf("Given inorder traversal as input\n");
48. for (i = 0;i< = 6;i++)
49. printf("%d->", arr[i]);
50. printf("\npreorder traversal of tree\n");
51. preorder(root);
52. printf("\ninorder traversal of tree\n");
53. inorder(root);
54. printf("\npostorder traversal of tree\n");
55. postorder(root);
56. break;
57. case 2:
58. insert();
59. printf("\npreorder traversal of tree\n");
60. preorder(root);
61. printf("\nInorder traversal of tree\n");
62. inorder(root);
63. printf("\npostorder traversal of tree\n");
64. postorder(root);
65. break;
66. default:printf("enter correct choice");
67. }
68.}
69.
70./* To create a new node */
71.N* new(int val)
72.{
73. N* node = (N*)malloc(sizeof(N));
74.
75. node->value = val;
76. node->l = NULL;
77. node->r = NULL;
78. return node;
79.}
80.
81./* To create a balanced binary search tree */
82.N* bt(int arr[], int first, int last)
83.{
84. int mid;
85.
86. N* root = (N*)malloc(sizeof(N));
87. if (first > last)
88. return NULL;
89. mid = (first + last) / 2;
90. root = new(arr[mid]);
91. root->l = bt(arr, first, mid - 1);
92. root->r = bt(arr, mid + 1, last);
93. return root;
94.}
95.
96./* Insert a node in the tree */
97.void insert()
98.{
99. int arr1[] = {10, 30, 20, 90, 80, 60, 40}, i;
100.
101. printf("Given post order traversal array\n");
102. for (i = 0;i <= 6;i++)
103. {
104. printf("%d->", arr1[i]);
105. }
106. for (i = 6;i >= 0;i--)
107. {
108. create(arr1[i]);
109. if (root = = NULL)
110. root = temp;
111. else
112. search(root);
113. }
114.}
115.
116./*Create a node */
117.void create(int data)
118.{
119. temp = (N *)malloc(1*sizeof(N));
120.
121. temp->value = data;
122. temp->l = temp->r = NULL;
123.}
124.
125./* Search for the appropriate position to insert the new node */
126.void search(N *t)
127.{
128. if ((temp->value>t->value)&&(t->r != NULL))
129. search(t->r);
130. else if ((temp->value>t->value)&&(t->r == NULL))
131. t->r = temp;
132. else if ((temp->value<t->value)&&(t->l != NULL))
133. search(t->l);
134. else if ((temp->value<t->value)&&(t->l == NULL))
135. t->l = temp;
136.}
137.
138./* to display inorder of tree */
139.void inorder(N *t)
140.{
141. if (t->l != NULL)
142. inorder(t->l);
143. printf("%d->", t->value);
144. if (t->r != NULL)
145. inorder(t->r);
146.}
147.
148./* to display preorder traversal of tree */
149.void preorder(N *t)
150.{
151. printf("%d->", t->value);
152. if (t->l != NULL)
153. inorder(t->l);
154. if (t->r != NULL)
155. inorder(t->r);
156.}
157.
158./* to display postorder traversal of tree */
159.void postorder(N *t)
160.{
161. if (t->l != NULL)
162. inorder(t->l);
163. if (t->r != NULL)
164. inorder(t->r);
165. printf("%d->", t->value);
166.}
在上面的代码中，在 vi 中用空格替换数字的正确正则表达式是什么。 我想在 vi 中用空格替换行号。 我在互联网上搜索我得到了各种教程来将行号放入文件但是如果它们已经存在，如何替换行号？
最佳答案
您可以使用以下替换:
:%s/^\d\+\./ /
在哪里
^匹配行首\d\+匹配一个或多个数字\.匹配一个点//用空格替换
关于regex - 如何在vim中替换行号，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/51941340/