main.cpp - master - davinchi2kxx/projectSeminarTask2

main.cpp
115 строк3 KB
davinchi
first_commit
17 фев 2025, 23:26
17 фев 2025, 23:26037596c
#include <iostream>
#include <string>
#include <vector>
#include <cctype>

using namespace std;

vector<string> tokenize(const string &input) {
    vector<string> tokens;
    string current;
    for (char ch : input) {
        if (isalnum(ch)) {
            current += ch;
        } else {
            if (!current.empty()) {
                tokens.push_back(current);
                current.clear();
            }
            if (!isspace(ch)) {
                tokens.push_back(string(1, ch));
            }
        }
    }
    if (!current.empty()) {
        tokens.push_back(current);
    }
    return tokens;
}

bool isIdentifier(const string &str) {
    if (str.empty() || !isalpha(str[0])) return false;
    for (char ch : str)
        if (!isalnum(ch)) return false;
    return true;
}

bool isValidType(const string &str) {
    string types[] = {"integer", "long", "variant", "string"};
    for (const string &t : types)
        if (str == t) return true;
    return false;
}

bool fsm(const string &input) {
    enum State { START, DIM, IDENTIFIER, COMMA, AS, TYPE, END };
    State state = START;
    vector<string> tokens = tokenize(input);
    
    for (const string &token : tokens) {
        switch (state) {
            case START:
            case END:
                if (token == "dim") {
                    state = DIM;
                } else {
                    return false;
                }
                break;
            case DIM:
                if (isIdentifier(token)) {
                    state = IDENTIFIER;
                } else {
                    return false;
                }
                break;
            case IDENTIFIER:
                if (token == ",") {
                    state = COMMA;
                } else if (token == "as") {
                    state = AS;
                } else {
                    return false;
                }
                break;
            case COMMA:
                if (isIdentifier(token)) {
                    state = IDENTIFIER;
                } else {
                    return false;
                }
                break;
            case AS:
                if (isValidType(token)) {
                    state = TYPE;
                } else {
                    return false;
                }
                break;
            case TYPE:
                if (token == ",") {
                    state = COMMA;
                } else if (token == ";") {
                    state = END;
                } else {
                    return false;
                }
                break;
        }
    }
    return state == END || state == TYPE;
}

int main() {
    string input;
    cout << "Enter a declaration: ";
    getline(cin, input);
    
    if (fsm(input)) {
        cout << "Valid declaration" << endl;
    } else {
        cout << "Invalid declaration" << endl;
    }
    
    return 0;
}