// Demonstrate use of "String Streams"
// George F. Riley, Georgia Tech, Fall 2009


// The C library "sprintf" (print to a string) is extremely useful
// when we have an integer value and we need an ascii string representation
// of that integer.  For example, we want to create 10 files with names
// "file01", "file02" .. "file09".  In C programming we would use sprintf
// to create the file name into a temporary working "char" buffer.
// In C++, we can solve the problem using the stringstream class, in 
// a more portable and safe way.

#include <iostream>
#include <iomanip>
#include <sstream>

using namespace std;

int main()
{
  for (int i = 0; i < 10; ++i)
    {
      ostringstream sstr;
      sstr << "file" << setw(2) << i;
      // Writing to the stringstream object sstr does not create a file
      // but instead writes to a C++ std::string object.
      string fn = sstr.str();
      cout << "File name is " << fn << endl;
    }
  // Similarly we can create an input stringstream that is given an existing
  // string, and that string is used as the data for the stream reads.
  ostringstream ostr;
  for (int i = 0; i < 10; ++i)
    {
      ostr << i << " ";
    }
  istringstream istr(ostr.str());
  cout << "istr constructed with " << ostr.str() << endl;
  for (int i = 0; i < 10; ++i)
    {
      int k;
      // Reading from a istringstream object does not read a file
      // but instead reads from the initial string.
      istr >> k;
      cout << "k is " << k << endl;
    }
}