operator overload

[Biotronic]

On Tuesday, 12 December 2017 at 15:52:09 UTC, dark777 wrote:
> I know that this community is not of c ++, but some time I have 
> been studying how to do overload of ostream operators in c ++ 
> and I even managed to get to this result but the same is not 
> converting to binary only presents zeros as output to any 
> number already tried to pass parameter of variable and yet he 
> is not getting the number for conversion how to solve it so 
> that it works correctly?
>
> PS: if I use the same conversion algorithm in a function it 
> converts normally it is not only converting to the output of 
> the operator ..
>
>
> https://pastebin.com/BXGXiiRk

This line:
     << "\n\t127 em binario:     " << bin << 127 << "\n\n";

Your hope is that the '<< bin' part should behave just like 
std::hex does, except binary instead of hex. Right?

I'm afraid that's not how C++ formatting works. You can see a 
hint of what happens in the output you get:
     127 em binario:     000000000000127

The zeroes are from the uninitialized int in your Bin struct, and 
the '127' is from the 127 you pass right after passing bin.

Translating to code that does not use operators, the behavior you 
expect is something like this:

     std::cout.print("\n\t127 em binario:     ");
     std::cout.setFormat(bin);
     std::cout.print(127); // Should use bin for formatting
     std::cout.print("\n\n");

The actual behavior is something like this:

     std ::cout.print("\n\t127 em binario:     ");
     std::cout.print(bin); // Prints the value stored in bin. That 
is, 0.
     std::cout.print(127); // Prints 127 just the way it would 
otherwise print it.
     std::cout.print("\n\n");

There is no way in C++ to set the format the way you want it. If 
you want binary output, you need to call a function like your 
binario function.

The point of overloading operator<<(std::ostream&, MyType) is not 
to format another type, but to be able to print MyType in a given 
way. Basically like toString() in D, C# or Java.

--
    Biotronic