int main(int argc, char* argv[])
{
vector<int> v(10,5); // 10 copies of 5
// sum of all elements of v
Sum<int> s;
s = for_each(v.begin(), v.end(), s);
cout << "the sum is " << s.result() << '\n';
return 0;
}
void f(list<double>& ls)
{
Sum<double> sum;
sum = for_each(ls.begin((), ls.end(), sum); // 对表中每一个元素调用sum()函数对象
cout << "the sum is " << sum.result() << endl;
}