SVN - Update Process

 Jerry had committed the first version of the code. But he thinks that he should write two functions to accept input and to display array contents. After modification, array.c looks as follows.

#include <stdio.h>
#define MAX 16

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, arr[MAX];

   printf("Enter the total number of elements: ");
   scanf("%d", &n);

   printf("Enter the elements\n");
   accept_input(arr, n);

   printf("Array has following elements\n");
   display(arr, n);

   return 0;
}

Jerry compiles and tests his code and is ready to commit changes. Before that, he wants to review the changes using the following command.

[jerry@CentOS trunk]$ svn diff

The above command will produce the following result.

Index: array.c
===================================================================
--- array.c   (revision 2)
+++ array.c   (working copy)
@@ -2,6 +2,24 @@
 
 #define MAX 16
 
+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, arr[MAX];
@@ -10,15 +28,10 @@
    scanf("%d", &n);
 
    printf("Enter the elements\n");
+   accept_input(arr, n);
 
-   for (i = 0; i < n; ++i)
-      scanf("%d", &arr[i]);
-
    printf("Array has following elements\n");
-   for (i = 0; i < n; ++i)
-      printf("|%d| ", arr[i]);
-   
-   printf("\n");
+   display(arr, n);
 
    return 0;
 }

For the new added lines, Subversion shows + sign before line and for removed line it shows - sign. Now, Jerry tries to commit the changes using the following command:

[jerry@CentOS trunk]$ svn commit -m "Add function to accept input and to display array contents"

The above command will produce the following result.

Sending        trunk/array.c
svn: Commit failed (details follow):
svn: File or directory 'array.c' is out of date; try updating
svn: resource out of date; try updating

Subversion is not allowing to commit Jerry's changes, because Tom has already modified the repository and Jerry's working copy is out of date. To avoid overwriting each other's changes, Subversion fails this operation. Jerry must update working copy before committing his changes. So he uses update command as shown below.

[jerry@CentOS trunk]$ svn update
G    array.c
Updated to revision 3.

Subversion is showing the letter G before filename, which means this file has been merged.

[jerry@CentOS trunk]$ svn diff

The above command will produce the following result.

Index: array.c
===================================================================
--- array.c   (revision 3)
+++ array.c   (working copy)
@@ -2,6 +2,24 @@
 
 #define MAX 16
 
+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, arr[MAX];
@@ -15,15 +33,10 @@
    }
 
    printf("Enter the elements\n");
+   accept_input(arr, n);
 
-   for (i = 0; i < n; ++i)
-      scanf("%d", &arr[i]);
-
    printf("Array has following elements\n");
-   for (i = 0; i < n; ++i)
-      printf("|%d| ", arr[i]);
-   
-   printf("\n");
+   display(arr, n);
 
    return 0;
 }

Subversion is showing only Jerry's changes, but array.c file is merged. If you observe carefully, Subversion is now showing revision number 3. In the previous output, it was showing revision number 2. Just review who made changes in the file and for what purpose.

jerry@CentOS trunk]$ svn log
------------------------------------------------------------------------
r3 | tom   | 2013-08-18 20:21:50 +0530 (Sun, 18 Aug 2013)   | 1 line

Fix array overflow problem
------------------------------------------------------------------------
r2 | jerry | 2013-08-17 20:40:43 +0530 (Sat, 17 Aug 2013) | 1 line

Initial commit
------------------------------------------------------------------------
r1 | jerry | 2013-08-04 23:43:08 +0530 (Sun, 04 Aug 2013) | 1 line

Create trunk, branches, tags directory structure
------------------------------------------------------------------------

Now Jerry's working copy is synchronized with the repository and he can safely commit his changes.

[jerry@CentOS trunk]$ svn commit -m "Add function to accept input and to display array contents"
Sending        trunk/array.c
Transmitting file data .
Committed revision 4.