How to Determine File Size in C Without External Libraries?

Determining File Size in C

How can I obtain the size of a file in C while maintaining portability, reliability, and simplicity, without incurring library dependencies?

Solution:

The most common and reliable method to determine file size in C is by utilizing the std::ifstream class. Here's how you can implement it:

#include <fstream>

std::ifstream::pos_type filesize(const char* filename)
{
    std::ifstream in(filename, std::ifstream::ate | std::ifstream::binary);
    return in.tellg();
}

In this code:

• std::ifstream(filename, std::ifstream::ate | std::ifstream::binary) opens the specified file for reading.
• std::ifstream::ate positions the file pointer at the end of the file.
• std::ifstream::binary ensures the file is read in binary mode.
• in.tellg() retrieves the current position of the file pointer, which represents the file size.

Note:
It's important to note that this solution uses tellg(), which doesn't always return the correct file size on certain systems. Refer to this discussion for additional information: http://stackoverflow.com/a/22986486/1835769.

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