http://golf.shinh.org/p.rb?word+triangles

word_triangles.cc

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

void print(const std::string &s, size_t i) {
    size_t len = s.length();
    size_t space_count = i < len ? i : len;
    for(size_t j = 0; j < space_count; ++j)
        std::cout << " ";
    if (space_count < len)
        std::cout << s.c_str() + i;
}
int main()
{
    using namespace std;
    vector<string> words;

    size_t max_len = 0;

    while(true)
    {
        string s;
        cin >> s;
        if (!cin)
            break;
        string t(s);
        if (max_len < t.length())
            max_len = t.length();
        words.push_back(t);
    }

    for (size_t i=0; i < max_len; ++i)
    {
        vector<string>::const_iterator start = words.begin();
        print(*start, i);
        for(start = start + 1; start != words.end(); ++start)
        {
            cout << " ";
            print(*start, i);
        }
        cout << endl;
    }
    return 0;
}