Chapter 6: excercise 6

#include "std_lib_facilities.h"

// Chapter 6 Exercise 6

/*
    English grammar
*/

bool is_noun(string str){
    vector<string>noun{"birds", "fish", "C++"};

    for (auto i = 0; i < noun.size(); ++i) {
        if (str == noun[i])
            return true;
    }
    return false;

}

bool is_verbs(string str) {
    vector<string>verbs{"rules", "fly", "swim"};
    for (auto i = 0; i < verbs.size(); ++i) {
        if (str == verbs[i])
            return true;
    }
    return false;
}

bool is_conjuction(string str) {
    vector<string>conjuction{"but", "or", "and"};
    for (auto i = 0; i < conjuction.size(); ++i) {
        if (str == conjuction[i])
            return true;
    }
    return false;
}

bool is_pretex(string str) {
    vector<string>pretex{"the"};
    for (auto i = 0; i < pretex.size(); ++i) {
        if (str == pretex[i])
            return true;
    }
    return false;
}

bool is_point(string str) {
    string poin = "."s;
    if (str == poin) {
        return true;
    }
    return false;
}

bool senteces() {
    string pr, no, verb, conj, pr1, no1, verb1, t4k;
    cin >> pr >> no >> verb >> conj >> pr1 >> no1 >> verb1 >> t4k;


    if (!is_pretex(pr))
        return false;

    if (!is_noun(no))
        return false;

    if (!is_verbs(verb))
        return false;

    if (!is_conjuction(conj))
        return false;

    if (!is_pretex(pr1))
        return false;

    if (!is_noun(no1))
        return false;

    if (!is_verbs(verb1))
        return false;

    if (is_point(t4k))
        return true;
}

int main() {
    bool a = senteces();
    if (a) {
        std::cout << "OK";
    }
    else
        std::cout << "ERROR";
}