Check out example codes for "foreach cpp". It will help you in understanding the concepts better.

Code Example 1

// C++ program to demonstrate use of foreach 
#include <iostream> 
  
int main() 
{ 
    int arr[] = { 10, 20, 30, 40 }; 
  
    // Printing elements of an array using 
    // foreach loop 
    for (int x : arr) 
        std::cout << x << std::endl; 
}

Code Example 2

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

void 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;
}

Code Example 3

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);
}

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