Space delimited dynamic input by user of unknown length

How can i get and then store a space delimited input in c++ from a user into an array ?

Most important part is that length is unknown and input should be by user during runtime

#include<iostream>
using namespace std;
int main() {
    int n=0;
    string names[3];
    int i = 0;
    while ( getline( cin, names[i]))
    {
        cout<<"i = "<<i<<"\n";
        cout<<names[i]<<"\n";
        i++;
        cout<<"i = "<<i<<"\n";
    }
    for(i=0;i<3;i++)
    {
        cout<<names[i];
    }
    return 0;
}