lab04/Задание 4.cpp

#include <iostream>
#include <fstream>
#include <cstring>
#include <cctype>

bool isValidFilename(const char* filename) {
    const char* invalidChars = "*\"<>?|";
    if (strpbrk(filename, invalidChars)) return false;

    char* colon = strchr(filename, ':');
    if (colon) {
        if (colon != filename + 1 || !isalpha(filename[0]) || colon[1] != '\\') return false;
    }

    const char* extension = strrchr(filename, '.');
    if (extension) {
        char ext[5];
        strncpy(ext, extension, 4);
        ext[4] = '\0';
        for (char& c : ext) c = tolower(c);
        if (strncmp(ext, ".txt", 4) != 0) return false;
    }
    return true;
}

int main() {
    char filename[256];
    std::cout << "Ââåäèòå èìÿ ôàéëà: ";
    std::cin.getline(filename, 256);

    if (!isValidFilename(filename)) {
        std::cerr << "Íåêîððåêòíîå èìÿ ôàéëà." << std::endl;
        return 1;
    }

    if (!strrchr(filename, '.')) {
        strcat(filename, ".txt");
    }

    std::ifstream file(filename, std::ios::binary);
    if (!file) {
        std::cerr << "Îøèáêà îòêðûòèÿ ôàéëà." << std::endl;
        return 1;
    }

    file.seekg(0, std::ios::end);
    std::streamsize fileSize = file.tellg();
    file.seekg(0, std::ios::beg);

    char* buffer = new char[fileSize + 1];
    file.read(buffer, fileSize);
    buffer[fileSize] = '\0';
    file.close();

    char searchString[256];
    std::cout << "Ââåäèòå ñòðîêó äëÿ ïîèñêà: ";
    std::cin.getline(searchString, 256);

    size_t searchLength = strlen(searchString);
    size_t count = 0;
    char* position = buffer;

    while ((position = strstr(position, searchString)) != nullptr) {
        ++count;
        position += searchLength;
    }

    std::cout << "×èñëî âõîæäåíèé ñòðîêè: " << count << std::endl;

    delete[] buffer;
    return 0;
}