iv)for_each loop: Apart from the standard loops such as “for, while and do-while,” C++  also allows using another functionality that solves the same purpose termed “for_each” loops. This loop accepts a function that executes over each of the container elements. 

This loop is defined in the header file “algorithm” and hence has to be included for this loop’s successful operation.

Advantages of for_each loop:

• It is versatile, i.e., it can work with any container.
• It reduces chances of errors one can commit using generic for loop
• It makes code more readable
• for_each loops improve the overall performance of code

Syntax:

for_each (InputIterator first, InputIterator last, Function fn)

Here,

• first − Input iterator to the initial position.
• last − Final iterator to the final position.
• fn − Unary function that accepts an element in the range as an argument.

Example:

#include <iostream>
#include <algorithm>
using namespace std;
int print_even(int n) {
    if (n % 2 == 0)
        cout << n << ' ';
}
int main() {
    int arr[5] = {1, 2, 3, 4, 5};     
    cout << "The Array contains the following even numbers" << endl;
    for_each(arr, arr + 5, print_even);
    return 0;
}
Output:
The array contains the following even numbers
2 4

for_each loop can be executed using the keyword “for.”

Example: 

#include <iostream>
using namespace std;
int main() {
    int arr[] = {1, 2, 3, 4};
    // Printing elements of an array using foreach loop 
    for (int x: arr)
        cout << x << ' ';
    return 0;
}
Output:
1 2 3 4