C++ program to find the longest word that's displayable on a seven segment display.

seven-segment-display-longest-word-finder.cpp

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

int main(int argc, char** argv) {
    if (argc == 1) {
        std::cout << "Usage: " << argv[0] << " <word list path>" << std::endl;
        return -1;
    }

    std::string allowed_chars = "abcdefhijlnoprstuy";

    std::vector<std::string> valid_words;
    std::ifstream wordlist(argv[1]);
    std::string current_word;
    while (std::getline(wordlist, current_word)) {
        bool valid_char = true;
        for (int i = 0; i < current_word.length() - 1; i++) {
            if (allowed_chars.find(current_word[i]) == std::string::npos) {
                valid_char = false;
                break;
            }
        }
        if (valid_char) {
            valid_words.push_back(current_word);
        }
    }

    int longest_index = 0;
    for (int i = 0; i < valid_words.size(); i++) {
        if (valid_words[i].length() - 1 > valid_words[longest_index].length() - 1) {
            longest_index = i;
        }
    }

    std::cout << valid_words[longest_index] << std::endl;
}