There are two types of replace operations allowed on any object that inherits from the class os_element_group .

Replace First

Use the function replace_first() to find the first occurrence of a key and replace it with another element. If no matching element is found, replace_first() returns false .

In the following example, five os_list_item objects are defined. The first four are assigned keys. The objects named item1 and item4 are given keys named my_first_key and my_last_key , respectively. A key named my_middle_key is given to the two middle list items, named item2 and item3 . A key is not given to the fifth list item, named replacement .

The ordered list containing only the first four items is then created and added to the Web page. Following this, the function replace_first() is called. It replaces the first occurrence of my_middle_key with the element replacement .

The list is inserted in the Web page twice to show the list both before and after the replace operation. The first list contains four elements named item1 , item2 , item3 , and item4 , respectively. The second list also contains four elements, but in this case the first occurrence of my_middle_key ( item2 ) is replaced with replacement .

Example <ospace/web/e xamples/replace1.cpp>


    #include <iostream.h>
#include <ospace/web.h>

int main()
  {
  os_page page( "Replace1 Example" );

  os_list_item  item1( "item1" );
  os_list_item  item2( "item2" );
  os_list_item  item3( "item3" );
  os_list_item  item4( "item4" );
  os_list_item  replacement( "replacement item" );

  item1.key( "my_first_key" );
  item2.key( "my_middle_key" );
  item3.key( "my_middle_key" );
  item4.key( "my_last_key" );

  os_ordered_list ol( "Before:" );
  ol << item1 << item2 << item3 << item4;
  page << ol;

  ol.replace_first( "my_middle_key", replacement );

  ol.header( "After: item2 has been replaced" );

  page << ol;
  cout << page;
  return 0;
  }

Replace All

Use the function replace_all() to find all occurrences of a key and replace them with another element. The function replace_all() returns the number of elements replaced. If no matching elements are found, no element is replaced and 0 (zero) is returned.

The following example is identical to the previous example with one exception: replace_all() is called to find all occurrences of my_middle_key and replace them with the element replacement .

The first list contains four elements named item1 , item2 , item3 , and item4 , respectively. The second list also contains four elements, but in this case all occurrences of my_middle_key ( item2 and item3 ) are replaced with replacement .

Example <ospace/web/e xamples/replace2.cpp>


    #include <iostream.h>
#include <ospace/web.h>

int main()
  {
  os_page page( "Replace2 Example" );

  os_list_item  item1( "item1" );
  os_list_item  item2( "item2" );
  os_list_item  item3( "item3" );
  os_list_item  item4( "item4" );
  os_list_item  replacement( "replacement item" );

  item1.key( "my_first_key" );
  item2.key( "my_middle_key" );
  item3.key( "my_middle_key" );
  item4.key( "my_last_key" );

  os_ordered_list ol( "Before:" );
  ol << item1 << item2 << item3 << item4;
  page << ol;

  ol.replace_all( "my_middle_key", replacement );

  ol.header( "After: item2 and item3 have been replaced" );

  page << ol;
  cout << page;
  return 0;
  }

Using Replace

Replace First

Example <ospace/web/e xamples/replace1.cpp>

Replace All

Example <ospace/web/e xamples/replace2.cpp>