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c++getnumberssizeline

C++ Get Total File Line Number

Is there a function I can use to get total file line number in C++, or does it have to be manually done by for loop?

#include <iostream>
#include <ifstream>

ifstream aFile ("text.txt");
if (aFile.good()) {
//how do i get total file line number?

}

text.txt

line1
line2
line3
Solution

  • There is no such function. Counting can be done by reading whole lines 

    std::ifstream f("text.txt");
std::string line;
long i;
for (i = 0; std::getline(f, line); ++i)
    ;

    A note about scope, variable i must be outside for, if you want to access it after the loop.

    You may also read character-wise and check for linefeeds 

    std::ifstream f("text.txt");
char c;
long i = 0;
while (f.get(c))
    if (c == '\n')
        ++i;