Re: removing elements from vector<int> using <algorithm>

From:

Barry <dhb2000@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Wed, 10 Oct 2007 18:41:15 +0800

Message-ID:

<feie02$ihp$1@news.cn99.com>

Michael DOUBEZ wrote:

arnuld a ?crit :

WANTED:
/* C++ Primer - 4/e
*
* Exercise: 9.26
* STATEMENT
* Using the following definition of ia, copy ia into a vector and
into a list. Use the single iterator form of erase to remove the
elements with odd values from your list * and the even values from your
vector.
  int ia[] = { 0, 1, 1, 2, 3, 5, 8, 13, 21, 55, 89 };
*
*/

WHAT I GET:

/home/arnuld/programming/c++ $ g++ -ansi -pedantic -Wall -Wextra
ex_09.26.cpp ex_09.26.cpp:
In function 'int main()': ex_09.26.cpp:43:
error: '_1' was not declared in this scope
/home/arnuld/programming/c++ $ [snip]
  std::remove_if( ivec.begin(), ivec.end(),
          _1 % 2 == 0 );
  [snip]

I am just trying to use Lambda from Std. Lib. Why it is the problem ?

There is no lambda in STL (for now).
Instead, you can use the std::modulus<> functor together with
std::bind2nd().

std::not2 is also needed, the Predicate looks like:
bind2nd(not2(modulus<int>()), 2))