char[] manipulation

[spudval]

I'm writting a multiple file handling program and need to build filename and path strings.

I want the user to be able to enter a path and then append the filename to the end of this. However when using strcat, the null termination character seems to be ignored

Can anyone show me what I am doing wrong and explain why.

Attached is a file listing and a jpeg of the output.

Many thanks for any help given.

#include <iostream>
#include <fstream>
#include <string>
#include <stdio.h>

using namespace std;

int main ()
{
int length;
string line;
char filename1[8] = "net.txt", out_f[8] = "out.txt", file1[80],file2[80],path[80];

cout << "Please Enter full path of first input file \n";
cout << "eg : C:dir1\\dir2\\ \n";							//double \\ to display single \
cin.get(path,80);											//get file path

length = strlen(path);										//find path length					
cout << "\n" << length << "\n";
strncpy(file2,path,length);									//build full file name + path
strncat(file2,out_f,8);
//strcat(file2,"\0");
strncpy(file1,path,length);
strncat(file1,filename1,8);
//strcat(file1,"\0");

cout << "file paths built";				

cout << "\n";												//show whats going on
cout << "path " << path;
cout << "\n";
cout << "input " << file1 << "\n";
cout << "output " << file2 << "\n";

ifstream file_1 (file1);									//open file
	if (file_1)
	{														//succeeded
		ofstream file_2(file2,ios::out);
		while (!file_1.eof())								
		{													//read file
			getline (file_1,line);
			cout << line << endl;
			file_2 << line << endl;							//save in new file
		}
		file_1.close();
		file_2.close();
	}
	else cout << "error";
return 0;
}

[laserlight]

Please place your code in [code][/code] bbcode tags. At a glance, why are you not using C++ std::string when you have included the appropriate header?

[spudval]

I now have the code working, I didn't realise I had to load the char[] with a null before appending to it.

I'd like to use string, but the file handling commands (ifstream/ofstream) don't except them as valid parameters. I got compiler errors when I tried it.

Thanks anyway

[laserlight]

I'd like to use string, but the file handling commands (ifstream/ofstream) don't except them as valid parameters. I got compiler errors when I tried it.

There is the c_str() member function just for those times, e.g.,

std::string filename;
std::cin >> filename;
std::ifstream in(filename.c_str());

[spudval]

thanks i'll give it a go