Read part of txt file with C++

Question

I have a question regarding reading a *.txt file with C++. I'm trying to read only the part of data between some specific sign like [start] and [end].

How I can do that?

I know how to open and read the whole file but I don't know how to read only a part of it with such requirements.

Answer 1

Use std::string and std::getline to filter out lines and go from there. Example:

std::ifstream input("someText.txt");
std::string line;
unsigned int counter = 0;
while (std::getline(input, line))
{
    std::cout << "line " << counter << " reads: " << line << std::endl;
    counter++;
}

Furthermore you can use the substr() method of the std::string class to filter out sub strings. You can also tokenize words (instead of lines) with std::getline using the optional third argument, which is the tokenizer. Example:

std::ifstream input("someText.txt");
std::string word;
unsigned int counter = 0;
while (std::getline(input, word, ' '))
{
    std::cout << "word #" << counter << " is: " << word << std::endl;
    counter++;
}