File Comparison

[zawpai]

Hi,

Could anyone please check my sample code? I am a beginner in C++. This code is for file comparison. Whenever I run it, the compiling result is always "Usage: compiles <file1> <file2>".
I think something is wrong. Please give me some suggestions how to go through the code.

Best Regards,
zawpai

[Nick Evan]

Please post your code here instead of giving it as an attachment. I'm not going to open a zip file of 1.04 MB, that should contain code. 1.04 MB of text is rather much.

So just post your cpp file(s) here and be sure to use [code=cpp] //code here [/code] tags

[mitrmkar]

Try printing the arguments the program receives, I think you are simply not calling it correctly (maybe e.g. due to spaces in file paths)

if (argc != 3)
{
    cout << "Usage: compfiles <file1> <file2>\n";
    for(int ii = 0; ii < argc; ++ ii)
    {
        cout << "Arg# " << ii << " = " << argv[ii] << "\n";
    }
return 1;
}

[zawpai]

Hi niek_e,

The following is my sample code. Please check for me. Actually, I have already saved the two files in the same folder before doing the compiling my codes.

/*
	Create a file comparison utility.
*/

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

int main(int argc, char *argv[])
{
	register int i;
	//int numread;

	unsigned char buf1[1024], buf2[1024];

	if (argc != 3)
	{
		cout << "Usage: compfiles <file1> <file2>\n";
		return 1;
	}

	ifstream f1(argv[1], ios::in | ios::binary);
	
	if(!f1)
	{
		cout << "Can't open first file.\n";
		return 1;
	}

	ifstream f2(argv[2], ios::in | ios::binary);

	if (!f2)
	{
		cout << "Can't open second file.\n";
		return 1;
	}

	cout << "Comparing files.....\n";

	do
	{
		f1.read((char *) buf1, sizeof buf1);
		f2.read((char *) buf2, sizeof buf2);

		if (f1.gcount() != f2.gcount())
		{
			cout << "Files are of differing sizes.\n";
			f1.close();
			f2.close();
			return 0;
		}

		// compare contents of buffers
		for (i=0; i< f1.gcount(); i++)
		{
			if(buf1[i] != buf2[i])
			{
				cout << "Files differ.\n";
				f1.close();
				f2.close();
				return 0;
			}
		}
	}while(!f1.eof() && ! f2.eof());

	cout << "Files are the same.\n";

	f1.close();
	f2.close();
	
	
	return 0;
}

mitrmkar:
I have already test ur codes. I saw the value of 'argc' is zero. Do u have another good ideals?

Best Regards,
zawpai

[Nick Evan]

I saw the value of 'argc' is zero. Do u have another good ideals?

That's not possible, It should always be > 0. The first 'argv'(argv[0]) is always the program-name. (in your case 'compiles'?) and if you run the program with the two parameters as you programmed, argc should be 3 (programname, param1, param2).

When I run your program argc == 1; as it should be:

if (argc != 3)
{
	cout << "Usage: compfiles <file1> <file2>\n";
	cout << "argc="<< argc;
	return 1;
}

output: argc=1

p.s.: Next time you post code use [code=cpp] //code here [/code] tags as I mentioned before

[zawpai]

Hi niek_e,

I also don't know where the problem is exactly. Thank you for ur replying.

Best Regards,
zawpai

[John A]

You might want to try running your program from the command line as opposed to your IDE's built in console (I assume that's what you're using right now).

[zawpai]

Hi John A,

Your way will be corrected, but I can't still do well. My friend told me not to run the code and compile the exe file. He also told me after building my code, I will see the exe file. But, I can't see that file and where it is located.
How should I do command line compling?

Best Regards,
zawpai

[Nick Evan]

What compiler and OS are you using?

[zawpai]

Hi niek_e,

I run my codes in 'Microsoft Visual C++ 6.0'. I am using window XP.

Thanks,
zawpai

[Nick Evan]

I haven't used vc6 for a while (because the newer and free version 2008 is available)
But my guess is that you didn't release the build. Somewhere there should be a configurationmanager. In this you've probably selected 'debugbuild'. Change this to 'release' and the .exe should be made in your project-directory

[mitrmkar]

I run my codes in 'Microsoft Visual C++ 6.0'. I am using window XP.

Then, from the menu, open Project/Settings/Debug -tab. Supply the paths of the two files you want to cmpare in the 'Program arguments' field.

[zawpai]

Hi,

Now, I can compare the two files by using "mitrmkar's way". But, I need to find out how to create the exe file as "niek_e" told me.
Thanks all for giving the good suggestions.

Best Regards,
zawpai

[mitrmkar]

But, I need to find out how to create the exe file as "niek_e" told me.
Thanks all for giving the good suggestions.

From the menu, open Project/Settings/Linker -tab. You should see a field titled 'Output file name', there you can specify the file path/name for your program. The paths are relative to your project's path.
By default, there are two project build configurations available Release and Debug, The output file is specified on a per build configuration basis. You can switch the build configuration by selecting from the menu; Build/Set Active Configuration ...