Line by line reading in C and C++?

Question

I want to read line by line from a file in C or C++, and I know how to do that when I assume some fixed size of a line, but is there a simple way to somehow calculate or get the exact size needed for a line or all lines in file? (Reading word by word until newline is also good for me if anyone can do it that way.)

Answer 1

If you use a streamed reader, all this will be hidden from you. See getline. The example below is based from the code here.

// getline with strings
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main () {
  string str;
  ifstream ifs("data.txt");
  getline (ifs,str);
  cout << "first line of the file is " << str << ".\n";
}