The unique role of for_each () in function objects

For_each can traverse the values of list and vecotr, pass one of the values to the function object, call the () Operator for reload, and put the final calculation result into a function object to return. this function is otherAlgorithmNone. The usage is as follows.

 

# Include <iostream. h>
# Include <iterator>

# Include <string>

# Include <vector>
# Include <deque>
# Include <list>
# Include <algorithm>
# Include <map>
# Include <set>

Using namespace STD;

Class mean
{
Public:
Mean (): m_value (0), m_sum (0 ){}//
Void operator () (INT Ele) {m_value ++, m_sum + = ele;} // ELE is the value passed in by the overload function.
Public:
Int m_value;
Int m_sum;
};

Void main ()
{

Vector <int> m_vec (4 );
M_vec [0] = 1;
M_vec [1] = 2;
M_vec [2] = 3;
M_vec [3] = 4;

Mean Me = for_each (m_vec.begin (), m_vec.end (), mean (); // mean () to generate a temporary object, and for_each will call to generate a temporary object, then, call the () operator to reload the function through a temporary object. assign the final temporary object to me
Cout <me. m_sum <Endl; // The sum value is 10.
Cout <me. m_value <Endl; // The total number is 4
 

}