filterWords.cpp

#include <iostream>
#include <string>
#include <vector>

using namespace std;

int main()
{
    string words;
    string filter;
    string delimiter = " ";
    vector<string> splitwords;

    cout << "Please, enter words: ";
    getline (cin, words);
    cout << "Please, enter desired start letter(s): ";
    getline (cin, filter);

    while(words.size())
    {
        int index = words.find(delimiter);
        if(index != string::npos)
        {
            splitwords.push_back(words.substr(0, index));
            words = words.substr(index + delimiter.size());
            if(words.size() == 0) splitwords.push_back(words);
        }
        else
        {
            splitwords.push_back(words);
            words = "";
        }
    }
    
    for(int i = 0; i < splitwords.size(); i++) {
        if (splitwords[i].rfind(filter, 0) == 0)
        {
            cout << splitwords[i] << endl;
        }
    }

    return 0;
}