069.cpp

// STL : replace(), replace_if(), replace_copy() and replace_copy_if()

#include <iostream>
#include <algorithm>
#include <vector>

bool isOdd(int i)
{
    if (i % 2 != 0)
        return true;
    else
        return false;
}
int main()
{
    // program to understand the replace(), replace_if(), replace_copy() and replace_copy_if() function
    //  replace() : replaces elements from the specified range that are equal to the oldval with the newval
    // initializing a vector
    std::vector<int> v = {5, 3, 2, 8, 66, 2, 5, 9, 10};
    std::cout << "Vector : ";
    for (int i = 0; i < v.size(); i++)
    {
        std::cout << v[i] << " ";
    }
    std::cout << std::endl;

    // calling the remove function
    std::replace(v.begin(), v.end(), 5, 100);

    // printing the resultant vector
    std::cout << "Updated vector : ";
    for (int i = 0; i < v.size(); i++)
    {
        std::cout << v[i] << " ";
    }
    std::cout << std::endl;

    // initializing another vector
    std::vector<int> v2 = {3, 2, 4, 5, 6, 3, 4, 88, 12};
    std::cout << "Vector 2 : ";
    for (int i = 0; i < v2.size(); i++)
    {
        std::cout << v2[i] << " ";
    }
    std::cout << std::endl;

    // replace_if() : replace the element from the specified range for which the predicate func. is true
    std::replace_if(v2.begin(), v2.end(), isOdd, 100);
    // printing the resultant vector
    std::cout << "\nUpdated vector 2 : ";
    for (int i = 0; i < v2.size(); i++)
    {
        std::cout << v2[i] << " ";
    }
    std::cout << std::endl;

    std::vector<int> v3 = {5, 6, 7, 3, 4, 2, 5, 4, 6, 3, 7}, v4(7);
    // replace_copy(): it replaces the element from the specified range and puts it into the resultant vector. It also returns the end iterator for the resultant vector
    std::cout << "\nVector 3 : ";
    for (int i = 0; i < v3.size(); i++)
    {
        std::cout << v3[i] << " ";
    }
    std::cout << std::endl;
    std::vector<int>::iterator p, pend;
    pend = std::replace_copy(v3.begin(), v3.end(), v4.begin(), 4, 1000);
    // printing the resultant vector
    std::cout << "Updated vector 4 : ";
    for (p = v4.begin(); p != pend; p++)
    {
        std::cout << *p << " ";
    }
    std::cout << std::endl;

    std::vector<int> v5 = {5, 6, 7, 3, 4, 2, 5, 4, 6, 3, 7}, v6(7);
    // replace_copy_if(): it replaces the element from the specified range if predicate func returns true and puts it into the resultant vector. It also returns the end iterator for the resultant vector
    std::cout << "\nVector 5 : ";
    for (int i = 0; i < v5.size(); i++)
    {
        std::cout << v5[i] << " ";
    }
    std::cout << std::endl;
    pend = std::replace_copy_if(v5.begin(), v5.end(), v6.begin(), isOdd, 999);
    // printing the resultant vector
    std::cout << "Updated vector 6 : ";
    for (p = v6.begin(); p != pend; p++)
    {
        std::cout << *p << " ";
    }
    std::cout << std::endl;

    return 0;
}