for_each

function template

<algorithm>

std::for_each

template <class InputIterator, class Function>   Function for_each (InputIterator first, InputIterator last, Function fn);

Apply function to range

Applies function fn to each of the elements in the range [first,last).

The behavior of this template function is equivalent to:

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template<class InputIterator, class Function>  Function for_each(InputIterator first, InputIterator last, Function fn){  while (first!=last) {    fn (*first);    ++first;  }  return fn;      // or, since C++11: return move(fn);}

 

Parameters

first, last

Input iterators to the initial and final positions in a sequence. The range used is [first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.

fn

Unary function that accepts an element in the range as argument.
This can either be a function pointer or a move constructible function object.

Its return value, if any, is ignored.

Example

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// for_each example#include <iostream>     // std::cout#include <algorithm>    // std::for_each#include <vector>       // 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<int> 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;}

Edit & Run

Output:

myvector contains: 10 20 30myvector contains: 10 20 30

来自：http://www.cplusplus.com/reference/algorithm/for_each/?kw=for_each