How can i pass a file as a parameter in C++? - c++

Question

I want to do is basically writing a function which takes a parameter as a file name and if have multiple files, it will just take file name as a parameter and it should do this repetitively with a function. How can i do this?
Thanks.
Txt files are like this
for example, sorular.txt:
//What is the most crowded country in the world?
//China
//USA
//Germany
//Australia
//China
int main (){
string array [5];
string line;
string answer;
static int trueCount = 0;
static int falseCount = 0;
ifstream file("/Users/User/QuizMaker/Quiz Maker V2/sorular.txt");
if(file.is_open()){
cout << "Questions are loading... Please wait.."<<endl<<" ."<<endl<<" ."<<endl<<" ."<<endl;
while (!file.eof()) {
for (int i = 0; i<6; i++) {
getline(file,array[i]);
}
for (int a = 0; a<5; a++) {
cout << array[a] << endl;
}
cin >> answer;
if(answer == "C" || answer == "c") {
cout << true;
trueCount++;
}
else falseCount++;
}
cout << "You answered "<<trueCount << " questions as true" << endl;
cout << "You answered "<<falseCount << " questions as false" << endl;
file.close();
} else cout << " not ıoen";
cin.get();
return 0;
}

Answer 1

First let me say, that array cannot hold elements 0, 1, 2, 3, 4, and 5. It has only allocated 5 elements.
This may stretch your horizons a bit, but I think the right solution is a class here. So i'm going to hack this together, if you're interested you can research what I've done a bit and if you don't understand something feel free to ask in a comment.
class foo : public iterator<input_iterator_tag, string> {
const initializer_list<const char*> _files;
decltype(_files)::const_iterator _filesIt;
ifstream _file;
string _line;
void get() {
string array[6];
auto i = begin(array);
while (i != end(array) && getline(_file, *i)) {
advance(i, 1);
}
if (i == end(array)) {
_line = accumulate(cbegin(array), cend(array), string(), [](const auto& a, const auto& b) { return a.empty() ? b : a + '\n' + b; });
} else if(++_filesIt != cend(_files)) {
_file.close();
_file.open(*_filesIt);
get();
}
}
public:
foo() : _filesIt(cend(_files)) {}
foo(foo& rhs) : _files(rhs._files), _filesIt(next(cbegin(_files), distance(cbegin(rhs._files), rhs._filesIt))), _line(rhs._line) {
if (_filesIt != cend(_files)) {
_file.open(*_filesIt);
_file.seekg(rhs._file.tellg());
}
}
foo(const initializer_list<const char*>&& files) : _files(files), _filesIt(cbegin(_files)), _file(*_filesIt) { get(); }
const string& operator*() const { return _line; }
const foo& operator++() {
get();
return *this;
}
const foo operator++(int) {
foo result;
get();
return result;
}
bool operator==(const foo& rhs) { return distance(_filesIt, cend(_files)) == distance(rhs._filesIt, cend(rhs._files)); }
bool operator!=(const foo& rhs) { return distance(_filesIt, cend(_files)) != distance(rhs._filesIt, cend(rhs._files)); }
};
Though this class may seem overwhelming it greatly simplifies the rest of what you're trying to acompilsh. With this class the rest of your code will read:
auto true_count = 0;
auto false_count = 0;
for_each(foo({"/Users/User/QuizMaker/Quiz Maker V2/sorular.txt", "foo.txt", "bar.txt"}), foo(), [&](const auto& i) {
string answer;
cout << i << endl;
cin >> answer;
if(answer == "C" || answer == "c") {
cout << 1;
true_count++;
} else {
false_count++;
}
});
cout << "You answered "<< trueCount << " questions as true" << endl << "You answered " << falseCount << " questions as false" << endl;