我想在for_each的时候把满足equal函数的条件的变量加到list里：

Advertisement* equal(Listing &list, string keyword)(Advertisement* ad)
{
    if (ad->getTitle().find(keyword.c_str()) != -1)
        list.add(ad);
    return ad;
}

Listing Listing::filter(string keyword)
{
    if (keyword == "")
        return *this;

    Listing list;
    for_each(this->begin(), this->end(), equal(list,keyword));

使用find_if()
int a[8]={1,2,3,4,5,6,7,8};
list<int> list1(a,a+8);

class Equa
{
public:
    bool operator()(int keyword)
    {
        return keyword%2;            //满足条件？
    }
};

int main(int argc, char* argv[])
{
    list<int> list2;                    //相当你的Listing list;
    list<int>::iterator it,it2;           //it 指向你的this
    for(it=list1.begin();it!=list1.end();)   
    {
        it2=find_if(it,list1.end(),Equa());
        if(it2!=list1.end())
        {list2.push_back(*it2);it=it2;}
        it++;
    }    
    return 0;
}

没猜错的话 版主写的是游戏贴图时查找图片资源吧？ hehe - -#

template<class _II, class _Fn> inline
    _Fn for_each(_II _F, _II _L, _Fn _Op)
    {for (; _F != _L; ++_F)
        _Op(*_F); //虽然只传了一个参数，但可以用有默认值的参数           
    return (_Op); }

Advertisement* equal(string keyword，Listing &list）
//list需要有默认值   要不你使用个全局的list

谢谢你，我的问题已经解决了。我用了一个类
// A class that used for accept the function parameters
class Equal
{
private:
    string keyword;        // The value of keyword
    Listing &list;        // The list to add Advertisement*
public:
    // Constructor initializes the value of Listing list and string keyword
    Equal (Listing &init_list  ,const string init_keyword)
        : list(init_list) ,keyword ( init_keyword )
    {}

    // The function call for the element
    void operator ( ) ( Advertisement* elem ) const
    {
        if (elem->getTitle().find(keyword) != -1 ||
            elem->getBody().find(keyword) != -1)
        {
            list.add(elem);
        }
    }
};

// Return a Listing object that contains those advertisements
// whose name or description contains keyword
Listing Listing::filter(string keyword)
{
    if (keyword == "")
        return *this;

    Listing list;
    for_each(this->begin(), this->end(), Equal(list, keyword));

    return list;
}