Re: Real data for a change in the assignment operators and Bounded_String discussions.

[Hyman Rosen <hyrosen@mail.com>]

Robert I. Eachus wrote:
> I originally posted a working Ada program, with output.  Would you care 
> to do the same for your C and/or C++ versions?

Sorry about that. I read your code too hastily and misinterpreted
what it was doing. Here we go -

#include <fstream>
#include <iostream>
#include <iterator>
#include <vector>
#include <iomanip>
#include <ctype.h>

template <typename In, typename Out, typename Pred>
Out copy_if(In b, In e, Out o, Pred p)
{
     for (; b != e; ++b)
         if (p(*b))
             *o++ = *b;
     return o;
}

void process(std::istream &in, std::ostream &out)
{
     typedef std::vector<char> buf_type;
     buf_type buf;
     copy_if(std::istream_iterator<char>(in),
             std::istream_iterator<char>(),
             std::back_inserter(buf),
             isdigit);
     buf_type::iterator b = buf.begin(), e = buf.end();
     unsigned long c1d[10] = { 0 }, c2d[10][10] = { 0 };
     out << "There were " << buf.size() << " digits.\n\n";
     while (b != e)
     {
         char d = *b++ - '0';
         ++c1d[d];
         if (b != e)
             ++c2d[d][*b - '0'];
     }
     for (int i = 0; i < 10; ++i)
         out << i << "=" << std::setw(3) << c1d[i] << " ";
     out << "\n\n";
     for (int j = 0; j < 10; ++j)
     {
         for (int i = 0; i < 10; ++i)
             out << j << i << "=" << std::setw(3) << c2d[j][i] << " ";
         out << "\n";
     }
}

int main(int c, char **v)
{
     std::ifstream is;
     if (c > 1) is.open(v[1]);
     std::ofstream os;
     if (c > 2) os.open(v[2]);
     process(is.is_open() ? is : std::cin,
             os.is_open() ? os : std::cout);
}