Thread: Assigning the content of one map to another map and doing the same with vector

Originally Posted by pianorain

Code smell - Wikipedia, the free encyclopedia

Oh wow...I didn't know there is a programming term called "code smell". Thanks for the link.

Yes, that's clear. However, you still haven't given us any code with which we can help you. Why not try something like this:

Code:

{//local stringstream instead of...whatever scope it's at now.
   std::stringstream currentEnumeratorValue_ss;
   currentEnumeratorValue_ss << currentEnumeratorValue_i;
   if (!currentEnumeratorValue_ss.good()) {
       cout<< "Not good..." <<endl;
       cout<< "Value was not added to stringstream." <<endl;
   }
   //use .get() to get the string
   currentEnumeratorValue_s = currentEnumeratorValue_ss.get();
   if (!currentEnumeratorValue_ss.good()) {
       cout<< "Not good..." <<endl;
       cout<< "Stringstream did not insert value into string." <<endl;
   }
}
output_s += currentEnumeratorValue_s;

Using stringstream::get() didn't work either. It still failed at both inserting the int value of the enumerator into the stringstream, and outputting it to a string.

Should I be creating a new stringstream object each time I need one, instead of trying to use one object for all conversions of int to string? Also, do i need to pass anything to the stringstream's constructor, or is it ok to declare a stringstream like this:

Code:

stringstream currentEnumeratorValue_ss; //for converting the current enumerator value from an int to a string

And then use the << operator right away to insert values into it. Because that's what I'm currently doing.

Originally Posted by Programmer_P

Using stringstream::get() didn't work either. It still failed at both inserting the int value of the enumerator into the stringstream, and outputting it to a string.

I'm willing to bet that your stringstream isn't good even before your first integer insertion. You should check.

Originally Posted by Programmer_P

Should I be creating a new stringstream object each time I need one, instead of trying to use one object for all conversions of int to string?

You can reuse the same one over and over:

Code:

#include <sstream>
#include <iostream>
#include <string>

int main()
{
   std::stringstream s;
   for(int i = 0; i < 5; i++)
   {
      if(!s.good())
      {
         std::cout << "Not good - pre-insert" << std::endl;
      }

      s << i;
      if(!s.good())
      {
         std::cout << "Not good - post-insert" << std::endl;
      }

      std::string output = s.str();
      if(!s.good())
      {
         std::cout << "Not good - post-get()" << std::endl;
      }
      std::cout << output << std::endl;
      s.str(""); //clear the stringstream buffer
   }

   return 0;
}

Originally Posted by pianorain

I'm willing to bet that your stringstream isn't good even before your first integer insertion. You should check.

You were correct. It wasn't good before the first integer insertion dealing with the map.
An error bit must have been set probably before that in the code, possibly when dealing with the enumerator values vector...

Originally Posted by pianorain

s.str(""); //clear the stringstream buffer

If I remember correctly, you may also need to s.clear(); so as to reset any error flags the stringstream might be in. Personally, I think it is simpler to make the stringstream local to such a loop, unless due to performance reasons it turns out that you really need to pull it out of the loop.

Originally Posted by laserlight

If I remember correctly, you may also need to s.clear(); so as to reset any error flags the stringstream might be in. Personally, I think it is simpler to make the stringstream local to such a loop, unless due to performance reasons it turns out that you really need to pull it out of the loop.

You are correct; you should s.clear() if you're going to reuse the stringstream. I'd also prefer to make the stringstream local; keep the code simple until it's finished, then optimize where you need it.

Yep, this is where it first failed:

Code:

for (unsigned int i = 0; i < valuesOfEnumerators_v_i.size(); i++) {
      currentEnumeratorValue_i = valuesOfEnumerators_v_i.at(i); //get the current enumerator's value
      currentEnumeratorValue_ss<< currentEnumeratorValue_i;
      if (!currentEnumeratorValue_ss.good()) {
          cout<< "stringstream is no longer good. It failed when I attempted to insert an int into it.\n"
                      "We're at element " << i << " of the vector, which is: "
                 << valuesOfEnumerators_v_i.at(i) <<endl;
      }
      currentEnumeratorValue_ss>> currentEnumeratorValue_s;
      output_s += "    enumeratorValues.push_back(";
      output_s += currentEnumeratorValue_s; //add it to the output string
      output_s += ");\n";
}

Relevant output:

stringstream is no longer good. It failed when I attempted to insert an int into it.
We're at element 1 of the vector, which is: 0
stringstream is no longer good. It failed when I attempted to insert an int into it.
We're at element 2 of the vector, which is: 1
stringstream is no longer good. It failed when I attempted to insert an int into it.
We're at element 3 of the vector, which is: 2
stringstream is no longer good. It failed when I attempted to insert an int into it.
We're at element 4 of the vector, which is: 3
stringstream is no longer good. It failed when I attempted to insert an int into it.
We're at element 5 of the vector, which is: 4
stringstream is no longer good. It failed when I attempted to insert an int into it.
We're at element 6 of the vector, which is: 5

EDIT: Ok, so it fails at the second element of the vector of some reason (which is a 0).

Does the stringstream not like it when a 0 is inserted into it?
But that doesn't make any sense, since the first element of the vector was a 0 too, and that worked, while the second one failed...
Oh, maybe its because I need to clear the stringstream after using it for each iteration of the loop.

Would you mind humoring me and checking to see if the stringstream is good after you use operator>>? I'm willing to bet it's not.

Oh yeah...
Perfect. It works now.
Bout' time...
Seriously though, I don't get why a stringstream object wont overwrite any existing content when you use the << operator.

Originally Posted by pianorain

Would you mind humoring me and checking to see if the stringstream is good after you use operator>>? I'm willing to bet it's not.

Yeah, its still good. The problem was apparently the stringstream << operator either does not handle well when you attempt to insert a value that already exists in the stream, and/or it it does not handle inserting into a stream which already has something in it.

Either way, the problem is solved now.

Thanks everyone.

Originally Posted by whiteflags

Why should it magically clear()? You can append stuff to streams. It happens all the time with files... and cout...

I thought cout outputs whatever argument was passed to its parameter, and then clears itself.

An output like this:

Code:

int num = 10;
cout<< "You suck this amount of times: "  << num << endl;

I thought would first output the string, clear itself, output the number, clear itself, and then finally output the endl and clear itself. If it appends it, then why does using later cout statements without explicitly clearing the stream only output the new arguments being passed to cout?

Originally Posted by Programmer_P

Yeah, its still good. The problem was apparently the stringstream << operator either does not handle well when you attempt to insert a value that already exists in the stream, and/or it it does not handle inserting into a stream which already has something in it.

That doesn't seem right.

Code:

#include <sstream>
#include <iostream>
#include <string>

int main()
{
   std::stringstream s;
   for(int i = 0; i < 5; i++)
   {
      if(!s.good())
      {
         std::cout << "Not good - pre-insert" << std::endl;
      }

      s << 0;
      if(!s.good())
      {
         std::cout << "Not good - post-insert" << std::endl;
      }

      std::string output = s.str();
      if(!s.good())
      {
         std::cout << "Not good - post-get()" << std::endl;
      }
      std::cout << output << std::endl;
   }

   return 0;
}

The output is:

Code:

0
00
000
0000
00000

As you can see, it has both a repeated value and adding to a non-empty stringstream.

Originally Posted by pianorain

That doesn't seem right.

Code:

#include <sstream>
#include <iostream>
#include <string>

int main()
{
   std::stringstream s;
   for(int i = 0; i < 5; i++)
   {
      if(!s.good())
      {
         std::cout << "Not good - pre-insert" << std::endl;
      }

      s << 0;
      if(!s.good())
      {
         std::cout << "Not good - post-insert" << std::endl;
      }

      std::string output = s.str();
      if(!s.good())
      {
         std::cout << "Not good - post-get()" << std::endl;
      }
      std::cout << output << std::endl;
   }

   return 0;
}

The output is:

Code:

0
00
000
0000
00000

As you can see, it has both a repeated value and adding to a non-empty stringstream.

Maybe its a compiler specific issue then? I'm using GCC. What compiler are you using?
I'm about to try to compile your code in my compiler and see if I get the same results.

At any rate, clearing the stringstream after each operation in the loops fixed the problem (note that I call clear() after using both the << and >> operators). I don't know why, but it did.

EDIT: Hmm...I got the same results you did.