how to read the 150000 data from a txt file in a short period of time. I am now using getline and it costs about 23mins

Answer 1

What type of data are you reading and are you actually using all of the data that gets pulled or just particular data from the set?

Answer 2

Line-by-line triggers a 'too much overhead' thought for me. I've seen faster (by orders of magnitude) reading large blocks (ideally a multiple of disk cluster size), then parse for delimiters in-memory.

@Netkos is right to ask about the file + what you're doing though; my first response just comes from disliking line I/O. You could even have disk fragmentation, a busy system, a logic issue or flaky drive.

To focus on code, can you show some in CodePlayground and maybe a couple data lines?

Answer 3

something like surname, given name, telephone number and they are all string. I am now using getline(cin, input)

Answer 4

while (!myfile.eof()) {
// GET IT
getline(myfile, title, '\t');
getline(myfile, surname, '\t');
getline(myfile, givenName, '\t');

getline(myfile, phoneNumber, '\t');
getline(myfile, emailAddress, '\t');
getline(myfile, occupation, '\t');
getline(myfile, company);

char* temp = new char[phoneNumber.length() + 1];
char* temp_2 = new char[dayOfBirth.length() + 1];
strcpy(temp, phoneNumber.c_str());
strcpy(temp_2, dayOfBirth.c_str());
count = Hash_1.get_Key1(phoneNumber, dayOfBirth);

}

Hash_1.getKey1 is a function for generating keys