C++ Program to determine file size with just three lines of code

1. Use the iostream library of the Standard C++ to open an ifstream for reading a file.
2. Use seekg to position the get pointer at the end of the file. Technically at 0 bytes from the end, ios::end.
3. Next read its position using tellg. The function tellg returns the position from the start of the file in characters [unsigned char, i.e., bytes]. The value that tellg returns is the required file size.
4. This program can handle the largest file size that your OS, 32bit/64bit, can support. Hence, this method works on all file sizes.

The source code in C++

Compile using any C++ compiler. The code has self-explanatory comments.

#include <iostream>

#include <fstream>

using namespace std;

int main()
{

  // "C:\\Users\\Home\\Desktop\\cp.pdf" 
  const char* path = "path-to-file";

  // create an iftream 
  ifstream ifs(path);

  // if not success return 
  if (!ifs.is_open())
  {

    cout << "File not found.";

    return -1;

  }

  // position the pointer to the end 
  ifs.seekg(0, ios::end);

  // now print the file pointer 
  // position - the size is in 
  // bytes 
  cout << ifs.tellg() << endl;

  return 0;

}

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