My First C++0x (C++11) Program

hello_c++0x.cpp

#include <iostream>
#include <list>

using namespace std;

template <class T>
list<T> filter(bool (*f)(T x), list<T>* l) {
    list<T> result;
    typename list<T>::iterator it = l->begin();
    while(it != l->end()) {
        if(f(*it)) result.push_back(*it);
        it++;
    }
    return result;
}

template <class T>
list<T> map(T (*f)(T x), list<T>* l) {
    list<T> result;
    typename list<T>::iterator it = l->begin();
    while(it != l->end()) {
        result.push_back(f(*it++));   
    }
    return result;
}

template <class T>
int reduce(T (*f)(T x, T y), list<T>* l) {
    typename list<T>::iterator it = l->begin();
    T result = f(*it++, *it++);
    while(it != l->end()) {
        result = f(result, *it++);
    }
    return result;
}

int main() {
    list<int> l;
    for(int i=1; i<=5; i++) l.push_back(i);

    cout << reduce<int>([](int x, int y) { return x + y; }, &l) << endl;
    
    {
        list<int> p = map<int>([](int x) { return x * x; }, &l);
        list<int>::iterator it = p.begin();
        while(it != p.end()) {
            cout << *it++ << " ";
        }
        cout << endl;
    }
    {
        list<int> q = filter<int>([](int x) { return x % 2 == 0; }, &l);
        list<int>::iterator it = q.begin();
        while(it != q.end()) {
            cout << *it++ << " ";
        }
        cout << endl;
    }        
    return 0;
    
}

hello_python.py

l = range(1, 6)
print reduce(lambda x, y: x + y, l)
print map(lambda x: x*x, l)
print filter(lambda x: x%2 == 0, l)

Installed gcc46 (GCC 4.6) in Macports. hello_c++0x.cpp can be compiled as following:

g++-mp-4.6 -std=c++0x hello_c++0x.cpp

hello_python.py demonstrates how the same task can be done in Python.