Question

How to compare two text files in C++

Answer 1

#include <iostream>
#include <fstream>

using std::cout;
using std::endl;

int main()
{
	unsigned char buf1[1024] = { NULL }, buf2[1024] = { NULL };

	std::ifstream ifs("d:\\data.txt");
	ifs.read((char *)buf1, sizeof buf1);
	int size1 = ifs.gcount();
	ifs.close();
	ifs.clear();

	ifs.open("d:\\data.bak");
	ifs.read((char *)buf2, sizeof buf2);
	int size2 = ifs.gcount();
	ifs.close();

	if (size1 != size2) {
		cout << "Files not equal" << endl;
		return 0;
	}

	int i = 0;
	while (i < size1 && buf1[i] == buf2[i++]);

	if (i < size1) {
		cout << "Files not equal" << endl;
		return 0;
	}

	cout << "Files equal" << endl;

	return 0;
}

/*
run:

Files equal

*/

 

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