CODEWITHSUNDEEP
c++stringstream
FlyingMonkey
FlyingMonkey

Reputation: 51

Random characters in stringstream

I'm writing a program that searches for files. This block of code writes a folder name to a stringstream, preceding it with a "./" so that it can be used to change the directory. It then changes the directory and informs the user of the change.

stringstream maindir;
maindir << "./" << crntmainfile;
maindir.str().copy(maindirectory, 260, 0);
_chdir(maindirectory);
std::cout << maindirectory;
std::cout << "Main directory changed: " << maindirectory << "\n";

My problem is that maindirectory has a bunch of extra characters at the end. I'm assuming that this has to do with the fact that it's a 260 length array with maybe 20 characters in it and the extra characters are whatever happens to be occupying the unwritten memory. If this is my problem, how do I fix it?

EDIT: I've determined that crntmainfile is null terminated, but the terminator is lost when it's written to maindir. What's causing this? Does << simply not write null characters to stringstreams? How do I fix it?

EDIT: I solved my problem by doing maindir.put(0); after maindir << "./" << crntmainfile; to manually null terminate the string.

Upvotes: 1

Views: 1171

Answers (2)

yngccc
yngccc

Reputation: 5684

std::string::copy does not append a null character at the end of the copied content.

why don't you just do this

maindir << "./" << crntmainfile ;
maindir >> maindirectory;
maindir.clear();

Upvotes: 1

James Kanze
James Kanze

Reputation: 153919

std::string::copy doesn't '\0' terminate the target, so you have to do this yourself. A possibly better solution would be:

std::string mainDirectory( maindir.str() );
_chdir( mainDirectory.c_str() );

, and not use a char[] at all.

Upvotes: 2

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