c_cpp don_not_know_why.cpp

Posted 2021-05-14

// Every newline will find_first_of the inputting value, if can find, return pos, otherwise, continue to input.
// It can use for judging any one of the inputting values in the each line whether in the specified set.
// But I don't know it is why.
#include <iostream>
#include <vector>
#include <cstdlib>
#include <algorithm>
#include <iterator>

using namespace std;

int main() {
	vector<int> vec = { 32 };

  	// if one of inputting the value is in the vec, newline action will output the value, 
	// then over the procedure.
  	// However, if no one value is in the vec, I can continue to input.
	auto pos = find_first_of( istream_iterator<int>( cin ), istream_iterator<int>(),
							   vec.begin(), vec.end());
	if (pos != istream_iterator<int>()) {
		cout << *pos << endl;
	}

	system( "pause" );
	return 0;
}