Converting a numbers into a char

[GRex2595]

I'm doing a program that involves putting numbers into an array and then taking those numbers from the array and putting them into a string.

I've deduced that I need to convert the numbers into a char and put the char into the string individually, but when i use '0' + number or char(number), it doesn't change it. I still get @'s and x's.

fwd = fwd + char(num [fill]);

conv = '0' + num[fill];
fwd = fwd + conv

These are what I tried. conv is a char, num[fill] is an int array, and fwd is a string

[Mathhead200]

http://cplusplus.com/reference/iostream/stringstream/

int num[N] = { ... };
stringstream s;
for( int i = 0; i < N; ++i )
    s << num[i];
cout << s.str();

[GRex2595]

I'm sorry, but I don't quite get this. Is stringstream being used as a variable type here?

[Mathhead200]

Yes. stringstream is a type defined in the header file <sstream>. It is a type of iostream (like cout and cin) so it works the same. The difference is that a string stream isn't attached to the screen or keyboard, it's attached to a string (working as a buffer.) You can then call the method ss_var.str() (where ss_var is the name of your stringstream) to get that buffer.

Think about the code

1 2 3

int num[N] = { 1,2, 4, 2, 0, 5 }; for( int i = 0; i < N; ++i ) cout << num[i];

124205

So instead of printing them to screen, you print them to a string. Then you can get that string with the str() method.

[GRex2595]

Is s a string, or is s middle ground? What I need is something that will add the numbers of my array to one string and then add them in reverse to another string. How I get the numbers out of my array is easy enough. My biggest issue is trying to convert those numbers into a string. I see the s.str(), but that only looks like it will output the string of s. If I did fwd = s.str() would I still get the same result?

[Stewbond]

stringstream is an object type. It would be like using ifstream or ofstream if you know about reading and writing to files.

We use the stringstream type to declare an object called s. This is now our stream that we can use just like a cout or cin.

[Mathhead200]

Yes string fwd = s.str(); would store whats in the string stream into the a variable.

Just like with int x, stringstream s makes a variable called s that is type string steam.

[GRex2595]

Thanks. I'll try it

[zerobandwidth]

FYI pushing integers through a stringstream is not the most efficient method by far, but it is the easiest to learn and understand. Your most vocal resistance will likely come from old C purists. This trick works for any kind of number-to-string conversion in C++ that would, in Java, use one of the static Integer.toString(int) or similar functions.

As Mathhead200 noted above, you will need at least the following includes to make this work:

#include <sstream> // for stringstream type
#include <string> // for string type 

Note also that if you're displaying numbers and need to show an explicit sign for both positive and negative numbers, you can use the following trick:

string foo( int i )
{
  stringstream buf ( stringstream::out ) ; // Creates an output-only stream.

  buf << ( i >= 0 ? "+" : "" ) // Inserts a plus sign only if it's needed.
      << i ;

  return buf.str() ;
}

int main()
{
  for( int i = -2 ; i < 3 ; i++ )
    cout << foo(i) << endl ;
  return 0 ;
}

Output:

-2
-1
+0
+1
+2

[GRex2595]

Don't need a positive or negative sign for my code, but thank you for that. I might need it later