C++ transform for_each

#include<iostream>
#include<vector>
#include <list>
#include <algorithm>
#include <functional>

using namespace std;

// do not need to copy, fast
void Square (int & elementParam)
{
  elementParam = elementParam * elementParam;
}

// slow-parameters One Copy, One Copy return
int square2 (int elementParam)
{
  return elementParam * elementParam;
}

int main()
{
  vector<int> vec2;
  vector<int> vec3;

  for (int k=0;k<10;k++)
  {
    vec2.push_back(k);
    vec3.push_back(k);
  }

  for_each(vec2.begin(),vec2.end(),square);


  for (auto vec_iter2 = vec2.begin(); vec_iter2 != vec2.end(); ++vec_iter2)
  {
    cout << *vec_iter2 << " ";
  }
  cout << endl;
  cout << "------------------------------------------------------" << endl;


  for (auto vec_iter3 = vec3.begin(); vec_iter3 != vec3.end(); ++vec_iter3)
  {
    cout << *vec_iter3 << " ";
  }
  cout << endl;
  cout << "------------------------------------------------------" << endl;

  transform(vec3.begin(),vec3.end(),vec3.begin(),square2);
  for (auto vec_iter3 = vec3.begin(); vec_iter3 != vec3.end(); ++vec_iter3)
  {
    cout << *vec_iter3 << " ";
  }
  cout << endl;
  cout << "------------------------------------------------------" << endl;

  // transform flexible than for_each

 

       // for_each transform faster than the speed 


  system("pause");
  return 0;
}

 

=====================================================

0,149,162,536,496,481
---------------------------------------- --------------
0123456789
-------------------------- ----------------------------
0,149,162,536,496,481
------------ ------------------------------------------
press any key to continue...

 

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Origin www.cnblogs.com/herd/p/11008203.html