Re: Reading and Writing float value of infinity to file.

"Jim Langston" <tazmaster@rocketmail.com> wrote in message
news:Gc1Si.76$dr4.63@newsfe02.lga...


[Snip discussion about C++ not supporing infinity]

Well, this is what I came up with. Output is as I want. Do you see
anything I'm doing wrong here? Of course I'll have to come up with a better
name than "MyFloat".

1.#INF
1 2.2 3.3
1.#INF 2.2 3.3

#include <iostream>
#include <fstream>
#include <limits>
#include <string>

class MyFloat
{
public:
    MyFloat( float Value = 0.0f ): Value( Value ) {}
    operator float() { return Value; }
    float Value;
};

std::istream& operator>>( std::istream& is, MyFloat& mf )
{
    if ( is >> mf.Value )
    {
        if ( mf.Value == 1.0f && is.peek() == '#' )
        {
            std::string Rest;
            is >> Rest;
            if ( Rest == "#INF" )
                mf.Value = std::numeric_limits<float>::infinity();
        }
    }

    return is;
}

int main(void)
{
    float Infinity, Foo = 2.2f, Bar = 3.3f;
    Infinity = std::numeric_limits<float>::infinity();
    std::cout << Infinity << "\n";

    std::ofstream outf("test.txt");
    if ( outf.is_open() )
        outf << Infinity << " " << Foo << " " << Bar << "\n";

    outf.close();

    float Value = 0.0f, Value2 = 0.0f, Value3 = 0.0f;
    std::ifstream inf("test.txt");
    if ( inf.is_open() )
        inf >> Value >> Foo >> Bar;

    inf.close();

    std::cout << Value << " " << Foo << " " << Bar << "\n";

    MyFloat MyValue = 0.0f, MyValue2 = 0.0f, MyValue3 = 0.0f;
    std::ifstream inf2("test.txt");
    if ( inf2.is_open() )
        inf2 >> MyValue >> MyValue2 >> MyValue3;

    inf2.close();

    std::cout << MyValue << " " << MyValue2 << " " << MyValue3 << "\n";

    return 0;
}