Compare two file contents

[goldenswarna]

Hi
how to compare two text file contents in c++guide me ,

Thanks
sona

[VictorN]

Read the contents in two text (char/wchar_t/TCHAR) buffer or two CString objects and then compare these buffers/objects.

[goldenswarna]

this program works fine , but , i also check case insensitive for each string which function can i use

int main()
{

	int i, j=0,k=0;

	string s1,s,newcontent[10],oldcontent[10],addedcont[10];

    ifstream updatefile("test.txt");

	ifstream newfile("test2.txt");

	if(updatefile.is_open())
	{
		while(!(updatefile.eof()))
		{

			getline(updatefile,s1);

			oldcontent[j]=s1;
			j++;

		}
	}

	else
	{
		cout<<"filecannot open";

	}
	if(newfile.is_open())
	{
		while(!(newfile.eof()))
		{

			getline(newfile,s);

			newcontent[k]=s;

			k++;
	

		}
	}
	else
	{
		 cout<<"file cannto open";

	}
	for(i=0;i<10;i++)
	{
		if(newcontent[i].compare(oldcontent[i]) != 0)
		
		{
			addedcont[i]=newcontent[i];
			cout<<"new"<<addedcont[i];
		}

		
	}
	return 0;
}

[ProgramArtist]

Dear Goldenswarna,

after 45 posts: Please use code tags!
Your code is practically unreadable.

With regards
Programartist

[ProgramArtist]

Dear Goldenswarna,

thanks for adding code tags.

this program works fine

No. It doesn't. Only under certain circumstances it works fine:

If one (or both) of the files are longer then 10 lines (which was the case in my test) the program will crash. There is no check if your index ("magic" constant 10) overflows.

, but , i also check case insensitive for each string which function can i use

string::compare is always case sensitive.
To change that behaviour convert the strings into their upper case equivalents (or their lower case equivalents) using ctype::tolower (or ctype::toupper).

With regards
Programartist

[sunil_cguru]

Another option for case insensitive comparison is to use the stricmp function

[goldenswarna]

thanks sunilcguru and program artist ,how we avoid crash while in that case , is it possible to assign dynamic array?

if i use stricmp the parameters are passed case to c.str() format or how can i pass?

	if(stricmp(newcontent[i],oldcontent[i])!=0)
		{
			addedcont[i]=newcontent[i];
			cout<<"new"<<addedcont[i];
		}

the above code give error , gudie me

i got error char * ...'stricmp' : cannot convert parameter 1 from 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' to 'const char *'
        No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
Error executing cl.exe.

thanks

sona

[ProgramArtist]

Hi,

thanks sunilcguru and program artist ,how we avoid crash while in that case , is it possible to assign dynamic array?

Instead of using arrays use vectors. Are you familiar with vectors?
Using dynamically allocated arrays is not a good choice since you don't know the size at the beginning. So you'll need to reallocate them from time to time and that's what vector can do for you.

if i use stricmp the parameters are passed case to c.str() format or how can i pass?

    if(stricmp(newcontent[i],oldcontent[i])!=0)
        {
            addedcont[i]=newcontent[i];
            cout<<"new"<<addedcont[i];
        }

the above code give error , gudie me

i got error char * ...'stricmp' : cannot convert parameter 1 from 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' to 'const char *'
        No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
Error executing cl.exe.

thanks

Simple convert your std::string's to char* (with the public member function c_str():

    if(stricmp(newcontent[i].c_str(),oldcontent[i].c_str()) != 0)
        {
            addedcont[i] = newcontent[i];
            cout << "new" << addedcont[i] << "\n";
        }

Another thing:
I strongly recommend to use spaces between identifiers and operators!

If someone (like me) has to read

a=var1*var2/var3-var4;

I lose my head!

Please write:

a = var1 * var2 / var3 - var4;

instead!

With regards
Programartist

[goldenswarna]

Thanks Program Artist

i m dont know about vectors ? can u guide me , how we use vectors instead of array

Thanks
sona

[sunil_cguru]

Well as ProgramArtist already told you..vectors can grow dynamically at run time. You can find tons of articles on vectors. You can start with this.. http://www.cplusplus.com/reference/stl/vector/

[goldenswarna]

Thanks sunil guru

when i compare two files ,line by line , first time it ll show not matching line? after that when i updated a new line to the file , it ll show all the lines as not matched


Ex

file 1

hai how r u

file 2


hai how r u
hello

if i execute the above file format it show output as hello


after i added new line

file 1

hell
hai how r u

file 2

hai how r u

it will show the two lines as not match


how we will write files as appened at the beginning of the file

if my question is silly sorry for that

thanks
sona