C plus plus program for searching a word from text file?

Answer 1

#include<iostream>

#include<fstream>

#include<vector>

#include<string>

std::string get_input_file()

{

while (true)

{

std::cout << "Enter the input file name: ";

std::string filename;

std::getline (std::cin, filename);

std::ifstream file (filename);

if (file.is_open())

{

file.close();

return filename;

}

std::cerr << "The file could not be opened.\n" << std::endl;

}

}

std::string get_search_word()

{

while (true)

{

std::cout << "Enter the word to search for: ";

std::string search;

std::cin >> search;

if (search.size())

return search;

std::cerr << "The search word cannot be an empty string.\n" << std::endl;

}

}

std::vector<size_t> get_offsets(const std::string& filename, const std::string& search)

{

std::vector<size_t> offsets;

std::ifstream file (filename);

if (!file.is_open())

throw std::exception("The file could not be opened.");

size_t offset = 0;

while (!file.eof())

{

size_t pos = 0;

char c;

while (!file.read(&c, 1).eof() && c!=search[pos])

++offset;

while (pos!=search.size()-1 && !file.read(&c, 1).eof() && c==search[++pos]);

if (pos==search.size()-1 && c==search[pos])

offsets.push_back (offset);

offset += pos;

pos = 0;

}

file.close();

return offsets;

}

int main()

{

std::cout << "Word Search\n" << std::endl;

std::string filename = get_input_file();

std::string search = get_search_word();

std::vector<size_t> offsets = get_offsets (filename, search);

std::cout << "The word was found " << offsets.size() <<

" time" << (offsets.size()==1?"":"s") << ".\n" << std::endl;

if (offsets.size())

{

std::cout << "Offsets:\n";

for (auto off : offsets)

std::cout << off << std::endl;

}

}