Help

[mariuss]

My code do this
ex1
txt1
line 1
txt2
line1
out put
line 1

is ok but if I have
txt1
line 1
txt2
line 1
line 1
output
line1
line1

I need 1 time in output...help

  #include <fstream>    
#include <iostream>
#include <string>
using namespace std;



int main(int argc, char* argv[])
{
	ifstream input;
	ifstream compare;
	ofstream output;
	string line_input, line_compare;

	input.open(argv[1]);
	output.open(argv[3]);

	while (!input.eof())
	{
		getline(input, line_input);

		compare.open(argv[2]);
		while (!compare.eof())
		{
			getline(compare, line_compare);


			if (line_input == line_compare)
			{
				output << line_input << endl;
			}
		}
		compare.close();

	}

	cout << endl;
	input.close();
	output.close();

	system("pause");
	return 0;
}

[MiiNiPaa]

It is like merge + unique:
http://en.cppreference.com/w/cpp/algorithm/merge
http://en.cppreference.com/w/cpp/algorithm/unique_copy
Or set intersection ( http://en.cppreference.com/w/cpp/algorithm/set_intersection ) depending on other unknown requirements of your assigment.

If your ranges are not sorted, you will have to store file data in your program. There is no on-line way to do that.

[mariuss]

i need this
exemple
txt1
line 1
txt2
line 1
line 1
output
line1

only time no 2 times

[coder777]

You get the duplicates due to this:

while (!input.eof())
	{
		getline(input, line_input); // continues even ef getline(...) detects the eof

		compare.open(argv[2]);
		while (!compare.eof())
		{
			getline(compare, line_compare); // continues even ef getline(...) detects the eof
...

change to

while (getline(input, line_input)) // getline(...) returns [indirectly] true if anything is ok and false otherwise (eof)
	{
		compare.open(argv[2]);
		while (getline(compare, line_compare))
		{
...

[mariuss]

It is not good
if I wont this

txt1
line 1
line 1
line 2
line 1

txt2
line 1
line 1
line 1
line 1

output
line 1
line 1
line 1
line 1
line 1
line 1

to many line help

[coder777]

According to your original post it seems that you want the output only if the line exists in both file, correct?

If so make two not nested loops.

First loop: Read the lines of the first file into a vector.

http://www.cplusplus.com/reference/vector/vector/?kw=vector


Second loop: Read line by line of the second file. Find the line in the vector.

http://www.cplusplus.com/reference/algorithm/find/?kw=find

If found (i.e. != input_vector.end()) -> output.

So change your code into two not nested loops. Add a vector for the first loop and use find for the if on line 28. Oh, and still avoid the duplicates.

[dhayden]

I think coder777's algorithm will still output duplicate lines if they appear in the second file. How about this:
First loop: read the lines of txt1 into a set (a set provides faster lookup than a vector)

Second loop: read txt2 line by line. Try to find it in the set.
if you find it then {
output the line
remove the line from the set
}

Removing the line from the set will prevent duplicates from appearing.

[mariuss]

I find it txt dhydan ;)