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 andlast, including the element pointed by first but not the element pointed bylast.

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.

Return value

• C++98
• C++11
• 
  

Returns fn.

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

Complexity

Linear in the distance betweenfirst and last: Applies fn to each element.

Data races

The objects in the range [first,last) are accessed (each object is accessed exactly once).
These objects may be modified if InputIterator is a mutable iterator type andfn is not a constant function.

Exceptions

Throws if fn throws or if any of the operations on iterators throws.
Note that invalid arguments cause undefined behavior.

See also

transform

Transform range (function template)

find

Find value in range (function template)

search

Search range for subsequence (function template)