A very common used approach to read records from a CSV-Database is to read reading line by line from the file with std::getline. Plese read here about this function.
Then this line is again put in a stream, the std::istringstream.
With that it is possible to use again formatted or unformatted stream extraction functions, like >> or std::getline, to extract parts from the string (stingstream).
And here especially useful is the std::getline function with delimiter. You can then extract parts of a string until a certain character is found, in your case the comma (',').
Then you need to use modern C++ elements to implement a solution. Data and methods operating on this data are put in a class or struct.
And to design the reality into your program, you would need a data type (struct) "Record" and a data type (struct) "Database".
And then things will evolve.
Please see one example below. You can build your solution on this proposal:
#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>
#include <iomanip>
// One record, so one row in the database
struct Record{
std::string ID{};
int no{};
std::string name{};
std::string day{};
std::string department{};
int number{};
std::string teacher{};
std::string days{};
std::string location{};
// For reading one record in SCV format from a stream with the C++ extraction operator >>
friend std::istream& operator >> (std::istream& is, Record& r) {
// We will read a complete line and check, if this was OK
std::string line{}; char c;
if (std::getline(is, line)) {
// Now we will put this line into a std::istringstream, so that we can extract
// parts of it using stream functions. Basically again std::getline
std::istringstream iss{ line };
// and now we tryt to extract all parts of the record from the std::istringstream
std::getline(iss, r.ID,',');
iss >> r.no >> c;
std::getline(iss>> std::ws, r.name, ',');
std::getline(iss, r.day, ',');
std::getline(iss, r.department, ',');
iss >> r.number >> c;
std::getline(iss >> std::ws, r.teacher, ',');
std::getline(iss, r.days, ',');
std::getline(iss, r.location, ',');
}
return is;
}
// For writing one record to a stream with the C++ inserter operator >> in CSV format
friend std::ostream& operator << (std::ostream& os, const Record& r) {
return os << r.ID << ',' << r.no << ',' << r.name << ',' << r.day << ',' << r.department << ',' <<
r.number << ',' << r.teacher << ',' << r.days << ',' << r.location;
}
};
struct Database {
// Here we will store all records
std::vector<Record> records{};
// This will read a complete CSV database from a stream
friend std::istream& operator >> (std::istream& is, Database& d) {
// Clear/delete potential existing old data
d.records.clear();
// Now read complete database from stream
for (Record r; is >> r; d.records.push_back(r))
;
return is;
}
// And this will write all records to a stream;
friend std::ostream& operator << (std::ostream& os, const Database& d) {
for (const Record& r : d.records)
os << r << '\n';
return os;
}
bool load(const std::string& path) {
// Open file and check, if it could be opened
std::ifstream ifs(path);
if (ifs) {
// Read all data
ifs >> *this;
}
else
// Show error message
std::cerr << "\n\n*** Error: Could not open file '" << path << "'\n\n";
// return status of operation
return not ifs.bad();
}
bool save(const std::string& path) {
// Open file and check, if it could be opened
std::ofstream ofs(path);
if (ofs) {
// Read all data
ofs << *this;
}
else
// Show error message
std::cerr << "\n\n*** Error: Could not open file '" << path << "'\n\n";
// return status of operation
return not ofs.bad();
}
// Please add all functions here to work with your data in the database
// Example: pretty print
void display() {
for (const Record& r : records)
std::cout << r.ID << '\n' << r.no << '\n' << r.name << '\n' << r.day << '\n' << r.department << '\n' <<
r.number << '\n' << r.teacher << '\n' << r.days << '\n' << r.location << '\n';
}
};
const std::string Filename{"database.txt"};
int main() {
Database database{};
database.load(Filename);
database.display();
database.save(Filename);
}
