对一个序列应用函数。可以是函数指针，或者是functor。

// for_each example#include 
     
           // std::cout#include 
      
           // std::for_each#include 
       
               // std::vectorvoid myfunction (int i) {  // function:  std::cout << ' ' << i;}struct myclass {           // function object type:  void operator() (int i) {std::cout << ' ' << i;}} myobject;int main () {  std::vector
        
          myvector;  myvector.push_back(10);  myvector.push_back(20);  myvector.push_back(30);  std::cout << "myvector contains:";  for_each (myvector.begin(), myvector.end(), myfunction);  std::cout << '\n';  // or:  std::cout << "myvector contains:";  for_each (myvector.begin(), myvector.end(), myobject);  std::cout << '\n';  return 0;}