从文件中计算新行无法正常工作

Question

I am trying to count new lines from my file, but it doesn't seem to work. It gives me result 0 when there is 1 new line. How can I fix this?

getline(file, newstring);
char line;
int lines = 0;
for (int i = 0; i < newstring.length(); i++)
{

    if(line== '\n')
    {
        lines++;
    }

}
cout << lines;

Answer 1

As I understand it, this may also provide what you need:

#include <iostream>
#include <algorithm>
#include <fstream>
int main()
{
    std::ifstream inFile("file");
    // DISPLAY number of `\n` characters
    std::cout << std::count(std::istreambuf_iterator<char>(inFile),
                            std::istreambuf_iterator<char>(), '\n') << std:: endl;
    inFile.seekg(0); // reset the inFile stream to the first caracter to be read
    /** this also works - thanks to @Armin Montigny for the suggestion*/
    // DISPLAY number of `\n` characters
    std::cout << std::count(std::istreambuf_iterator<char>(inFile),
                            {}, '\n');
}

If I have a file like this:

This would count 11 new lines characters.

Answer 2

std::getline reads an entire line (and only one; it's called "getline", not "getlines") up to the line-terminating character, but the result does not include that terminator.

You don't need to look inside the string, you can just count how many times std::getline succeeds.

int lines = 0;
while (getline(file, newstring))
{
    lines++;
}
cout << lines;