read one line including spaces and split the words by the spaces

split.cpp

#include <bits/stdc++.h>

using namespace std;

#define INF 2000000000
#define MOD 1000000007
typedef long long ll;
typedef pair<int, int> P;


int main()
{
	string s;
	getline(cin, s);

	cout << s << "\n";

	vector<string> list;
	stringstream ss(s);
	string item;
	while (getline(ss, item, ' ') && !item.empty()) {
		list.push_back(item);
	}


	for (int i = 0; i < list.size(); i++) {
		cout << list[i] << "\n";
	}
}

/*
$ ./a.out
a b c
a b c
a
b
c
*/