for_each and normal function

[Rajesh1978]

if we use the for_each function with one list and one normal function then for each element the function will be called.

Then what is the advantage of using function object with for_each.

#include<iostream>
#include<algorithm>
#include<list>
using namespace std;

void addElem(int &elem)
{
    elem +=10;
}

class AddValue
{
    private:
        //the value to add
        int theValue;
    public:
        //constructor initializes the value to add
        AddValue(int val) : theValue(val) {}

        //the function call for the element adds the value
        void operator() (int& elem) const
        {
            elem += theValue;
        }
};


int main()
{
    list<int>lst1;
    int cnt=1;
    for(;cnt<11;)
    {
        lst1.push_back(cnt++);
    }
    list<int>::const_iterator itr = lst1.begin();
    for_each(lst1.begin(),lst1.end(),addElem);
    for(;itr != lst1.end();++itr)
    {
        cout<< *itr << "  ";
    }
    for_each(lst1.begin(),lst1.end(),addElem);
    itr=lst1.begin();
    cout<<endl;
    for(;itr != lst1.end();++itr)
    {
        cout<< *itr << "  ";
    }
cout<<endl<<"------------------"<<endl;
    for_each(lst1.begin(), lst1.end(),AddValue(10));
    itr=lst1.begin();
    for(;itr != lst1.end();++itr)
    {
        cout<< *itr << "  ";
    }
    for_each(lst1.begin(), lst1.end(),AddValue(10));
    itr=lst1.begin();
    cout<<endl;
    for(;itr != lst1.end();++itr)
    {
        cout<< *itr << "  ";
    }
    cout<<endl;
    return 0;
}

If i see the above code the calling a normal function and calling a function object is giving same flexibility and output.

Then why what is the real advantage of using function object here.

[laserlight]

If i see the above code the calling a normal function and calling a function object is giving same flexibility and output.

Then why what is the real advantage of using function object here.

Change the code to perform adding by 20 instead of 10. You are not allowed to modify addElem or the AddValue class, or to create a new function or class.

[Rajesh1978]

I can just say Brilliant.

Thanks in one line u explained it very well