// 使用一个函数对象来保存状态
#include <algorithm>
#include <iostream>
#include <vector>
#include <list>
using namespace std;
template<typename elementType>
struct DisplayElementKeepCount {
// Hold the count in a member variable
int m_nCount;
// Constructor
DisplayElementKeepCount() {
m_nCount = 0;
}
// Display the element, hold count!
void operator ()(const elementType& element) {
++m_nCount;
cout << element << ' ';
}
};
int main() {
vector<int> vecIntegers;
for (int nCount = 0; nCount < 10; ++nCount)
vecIntegers.push_back(nCount);
cout << "Displaying the vector of integers: " << endl;
// Display the array of integers
DisplayElementKeepCount<int> mResult;
mResult = for_each(vecIntegers.begin() // Start of range
, vecIntegers.end() // End of range
, DisplayElementKeepCount<int>()); // function object
cout << endl << endl;
// Use the state stores in the return value of for_each!
cout << "'" << mResult.m_nCount << "' elements were displayed!" << endl;
return 0;
}