分支
分支创造了另一条发展线。当有人希望开发过程分叉到两个不同的方向时，这很有用。让我们假设您已经发布了版本1.0的产品，您可能想要创建新的分支，以便可以将2.0的开发与1.0的错误修复分开。在本节中，我们将看到如何创建，遍历和合并分支。Jerry因冲突而感到不高兴，因此他决定创建一个新的分支。
[jerry@CentOS project_repo]$ ls
branches tags trunk
[jerry@CentOS project_repo]$ svn copy trunk branches/jerry_branch
A branches/jerry_branch
[jerry@CentOS project_repo]$ svn status
A + branches/jerry_branch
[jerry@CentOS project_repo]$ svn commit -m "Jerry's private branch"
Adding branches/jerry_branch
Adding branches/jerry_branch/README
Committed revision 9.
[jerry@CentOS project_repo]$
现在，Jerry正在他的私人部门工作。他为数组添加了排序操作。杰瑞的修改后的代码如下所示。
[jerry@CentOS project_repo]$ cd branches/jerry_branch/
[jerry@CentOS jerry_branch]$ cat array.c
上面的命令将产生以下结果。
#include <stdio.h>
#define MAX 16
void bubble_sort(int *arr, int n)
{
int i, j, temp, flag = 1;
for (i = 1; i < n && flag == 1; ++i) {
flag = 0;
for (j = 0; j < n - i; ++j) {
if (arr[j] > arr[j + 1]) {
flag = 1;
temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
void accept_input(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
scanf("%d", &arr[i]);
}
void display(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
printf("|%d| ", arr[i]);
printf("\n");
}
int main(void)
{
int i, n, key, ret, arr[MAX];
printf("Enter the total number of elements: ");
scanf("%d", &n);
/* Error handling for array overflow */
if (n >MAX) {
fprintf(stderr, "Number of elements must be less than %d\n", MAX);
return 1;
}
printf("Enter the elements\n");
accept_input(arr, n);
printf("Array has following elements\n");
display(arr, n);
printf("Sorted data is\n");
bubble_sort(arr, n);
display(arr, n);
return 0;
}
Jerry编译并测试他的代码，并准备提交更改。
[jerry@CentOS jerry_branch]$ make array
cc array.c -o array
[jerry@CentOS jerry_branch]$ ./array
上面的命令将产生以下结果。
Enter the total number of elements: 5
Enter the elements
10
-4
2
7
9
Array has following elements
|10| |-4| |2| |7| |9|
Sorted data is
|-4| |2| |7| |9| |10|
[jerry@CentOS jerry_branch]$ svn status
? array
M array.c
[jerry@CentOS jerry_branch]$ svn commit -m "Added sort operation"
Sending jerry_branch/array.c
Transmitting file data .
Committed revision 10.
与此同时，在后台操作，Tom决定实施搜索操作。Tom添加了用于搜索操作的代码，他的代码如下所示。
[tom@CentOS trunk]$ svn diff
上面的命令将产生以下结果。
Index: array.c
===================================================================
--- array.c (revision 10)
+++ array.c (working copy)
@@ -2,6 +2,27 @@
#define MAX 16
+int bin_search(int *arr, int n, int key)
+{
+ int low, high, mid;
+
+ low = 0;
+ high = n - 1;
+ mid = low + (high - low) / 2;
+
+ while (low <= high) {
+ if (arr[mid] == key)
+ return mid;
+ if (arr[mid] > key)
+ high = mid - 1;
+ else
+ low = mid + 1;
+ mid = low + (high - low) / 2;
+ }
+
+ return -1;
+}
+
void accept_input(int *arr, int n)
{
int i;
@@ -22,7 +43,7 @@
int main(void)
{
- int i, n, arr[MAX];
+ int i, n, ret, key, arr[MAX];
printf("Enter the total number of elements: ");
scanf("%d", &n);
@@ -39,5 +60,16 @@
printf("Array has following elements\n");
display(arr, n);
+ printf("Enter the element to be searched: ");
+ scanf("%d", &key);
+
+ ret = bin_search(arr, n, key);
+ if (ret < 0) {
+ fprintf(stderr, "%d element not present in array\n", key);
+ return 1;
+ }
+
+ printf("%d element found at location %d\n", key, ret + 1);
+
return 0;
}
经过审查，他提交了更改。
[tom@CentOS trunk]$ svn status
? array
M array.c
[tom@CentOS trunk]$ svn commit -m "Added search operation"
Sending trunk/array.c
Transmitting file data .
Committed revision 11.
但是Tom很好奇Jreey在他的他的分支所做的事情。
[tom@CentOS trunk]$ cd ../branches/
[tom@CentOS branches]$ svn up
A jerry_branch
A jerry_branch/array.c
A jerry_branch/README
[tom@CentOS branches]$ svn log
------------------------------------------------------------------------
r9 | jerry | 2013-08-27 21:56:51 +0530 (Tue, 27 Aug 2013) | 1 line
Added sort operation
------------------------------------------------------------------------
通过查看Subversion的日志消息，Tom发现Jerry实现了“sort”操作。Tom使用二进制搜索算法实现了搜索操作，它总是希望数据按排序顺序。但是，如果用户以未排序的顺序提供数据怎么办？在这种情况下，二进制搜索操作将失败。因此，他决定在搜索操作之前采用Jerry的代码对数据进行排序。因此，他要求Subversion将来自Jerry分支的代码合并到主干中。
[tom@CentOS trunk]$ pwd
/home/tom/project_repo/trunk
[tom@CentOS trunk]$ svn merge ../branches/jerry_branch/
--- Merging r9 through r11 into '.':
U array.c
合并后，array.c将如下所示。
[tom@CentOS trunk]$ cat array.c
上面的命令将产生以下结果。
#include <stdio.h>
#define MAX 16
void bubble_sort(int *arr, int n)
{
int i, j, temp, flag = 1;
for (i = 1; i < n && flag == 1; ++i) {
flag = 0;
for (j = 0; j < n - i; ++j) {
if (arr[j] > arr[j + 1]) {
flag = 1;
temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
int bin_search(int *arr, int n, int key)
{
int low, high, mid;
low = 0;
high = n - 1;
mid = low + (high - low) / 2;
while (low <= high) {
if (arr[mid] == key)
return mid;
if (arr[mid] > key)
high = mid - 1;
else
low = mid + 1;
mid = low + (high - low) / 2;
}
return -1;
}
void accept_input(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
scanf("%d", &arr[i]);
}
void display(int *arr, int n)
{
int i;
for (i = 0; i < n; ++i)
printf("|%d| ", arr[i]);
printf("\n");
}
int main(void)
{
int i, n, ret, key, arr[MAX];
printf("Enter the total number of elements: ");
scanf("%d", &n);
/* Error handling for array overflow */
if (n > MAX) {
fprintf(stderr, "Number of elements must be less than %d\n", MAX);
return 1;
}
printf("Enter the elements\n");
accept_input(arr, n);
printf("Array has following elements\n");
display(arr, n);
printf("Sorted data is\n");
bubble_sort(arr, n);
display(arr, n);
printf("Enter the element to be searched: ");
scanf("%d", &key);
ret = bin_search(arr, n, key);
if (ret < 0) {
fprintf(stderr, "%d element not present in array\n", key);
return 1;
}
printf("%d element found at location %d\n", key, ret + 1);
return 0;
}
经过编译和测试后，Tom将更改提交到存储库。
[tom@CentOS trunk]$ make array
cc array.c -o array
[tom@CentOS trunk]$ ./array
Enter the total number of elements: 5
Enter the elements
10
-2
8
15
3
Array has following elements
|10| |-2| |8| |15| |3|
Sorted data is
|-2| |3| |8| |10| |15|
Enter the element to be searched: -2
-2 element found at location 1
[tom@CentOS trunk]$ svn commit -m "Merge changes from Jerry's code"
Sending trunk
Sending trunk/array.c
Transmitting file data .
Committed revision 12.
[tom@CentOS trunk]$
