Question

How to get the size of a file in C++

Answer 1

#include <iostream>
#include <fstream>

int main()
{
	std::streampos begin, end;
	std::ifstream afile("d:\\data.txt");

	begin = afile.tellg();

	afile.seekg(0, std::ios::end);
	end = afile.tellg();

	afile.close();

	std::cout << end - begin << std::endl;

	return 0;
}

/*
run:

15

*/

 

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Answer 2

#include <iostream>
#include <fstream>

int main() 
{
	const char *filename = "d:\\data.txt";

	std::ifstream in(filename, std::ifstream::ate | std::ifstream::binary);

	std::cout << in.tellg() << std::endl;

	return 0;
}

/*
run:

15

*/

 

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Answer 3

#include <iostream>
#include <fstream>

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

	return in.tellg();
}

int main() 
{
	const char *filename = "d:\\data.txt";

	std::cout << filesize(filename) << std::endl;

	return 0;
}

/*
run:

15

*/

 

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Answer 4

#include <iostream>
#include <fstream>

long filesize(std::string filename)
{
	struct stat stat_struct;

	int result = stat(filename.c_str(), &stat_struct);

	return result == 0 ? stat_struct.st_size : -1;
}


int main() 
{
	const char *filename = "d:\\data.txt";

	std::cout << filesize(filename) << std::endl;

	return 0;
}

/*
run:

15

*/

 

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Answer 5

#include <iostream>
#include <fstream>

int main()
{
	std::streampos size;

	std::ifstream file("d:\\data.bin", std::ios::ate);

	if (file.is_open())
	{
		size = file.tellg();

		file.close();

		std::cout << size << std::endl;
	}
	else std::cout << "Error open file" << std::endl;

	return 0;
}

/*
run:

23

*/

 

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Answer 6

#include <iostream>
#include <fstream>

int main() 
{
	std::streampos size;

	std::ifstream file("d:\\data.txt", std::ios::ate);

	if (file.is_open())
	{
		size = file.tellg();
		
		file.close();

		std::cout << size << std::endl;
	}
	else std::cout << "Error open file" << std::endl;

	return 0;
}

/*
run:

15

*/

 

70+ SQL courses for beginners and professionals