Проверка введенного текста на правильность

#include <iostream>
#include <string>
 
int main()
{
    const std::string for_search("lol");
    const std::string for_replace("wtf?!");
    std::string tmp;
    while(std::cin >> tmp)
    {
        if(tmp == for_search)
            std::cout<<for_replace<<'\n';
    }
    return 0;
}

#include <iostream>
#include <string>
 
int main()
{
    std::string word;
 
    while (std::cin >> word)
        if (word == "lol")
            std::cout << "Ololo!!!!!!!11" << std::endl;
 
    return 0;
}

std::pair<std::string, std::string> dictionary[] = {
  std::make_pair("лол", "ананасы...."),
  // ..
};
 
std::string word;
std::getline(std::cin, word);
 
for (std::size_t i = 0; i < sizeof(dictionary) / sizeof(dictionary[0]); ++i)
  if (word == dictionary[i].first)
    std::cout << dictionary[i].second << std::endl;

#include <iostream>
#include <string>
#include <vector>
#include <fstream>
 
std::string check(const std::string& one, const std::vector<std::string>& vec)
{
    std::string result;
    for(std::vector<std::string>::const_iterator iter=vec.begin(); iter != vec.end(); ++iter)
    {
            std::pair<std::string::const_iterator, std::string::const_iterator> it=std::mismatch(one.begin(), one.end(), iter->begin());
            std::string::difference_type differ=std::distance(one.begin(), it.first);
            if(differ == 0)
            {
                continue;
            }
            else if(differ == one.size())
            {
                return result=std::string("String is correct");
            }
            result="Correct word is\n";
            result+=*iter;
            break;
    }
    if(result.empty())
        result=std::string("There is no such word\n");
    return result;
}
 
int main()
{
    std::string in_f_name;
    std::cout<<"Enter name of file for input\n";
    std::cin>>in_f_name;
    std::ifstream ifs(in_f_name.c_str());
             if(!ifs)
             {
                 std::cerr<<"Error with opening file "<< in_f_name <<'\n';
                 return 1;
             }
    std::vector<std::string> correct_words;
    std::string tmp;
    while(ifs >> tmp)
        correct_words.push_back(tmp);
    std::string for_check;
    while(std::cout<<"Enter string for check\n" && std::cin>>for_check)
    {
        std::cout<<check(for_check, correct_words)<<'\n';
    }
    return 0;
}