what does copy_if c++
//C++ STL program to demonstrate use of
//std::copy_if() function
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
//declaring & initializing an int array
int arr[] = { 10, 20, 30, -10, -20, 40, 50 };
//vector declaration
vector<int> v1(7);
//copying 5 array elements to the vector
copy_if(arr, arr + 7, v1.begin(), [](int i) { return (i >= 0); });
//printing array
cout << "arr: ";
for (int x : arr)
cout << x << " ";
cout << endl;
//printing vector
cout << "v1: ";
for (int x : v1)
cout << x << " ";
cout << endl;
return 0;
}