streams again

[zeeshan708]

we say that iostream is a class template specialization for char i/o for C++ standard library class basic_iostream then why does it also does i/o other than char type.

[Banfa]

The char refers to the data type of the output (or input) stream. A stream is a long series of values and each value has a type. For a char stream each value has type char but (in theory) you can have a stream of any type.

The classes convert from the stream to the type that you are interested in inputing/outputing.

[weaknessforcats]

You can use basic_iostream<char> if you want. iostream s just a typedef of this.

You can also use basic_iostream<wchar_t>. This is typedef'd to wiostream.

char and wchar_t are the only types you can use with basic_iostream.

[zeeshan708]

ya but when we include iostream and do some output of int data type how come it works?

[mac11]

As Banfa said, the stream converts types for you.

When you do, for instance:

cout << 5;

What prints is the text string "5", which is ascii or unicode or whatever to represent the character 5 as TEXT. It does not send the actual value 5 - if it did you would see some nonprintable character rather than a nice 5. The stream is smart and when you send it an int it converts it to text.

If you want to dump raw binary representation of an int you can do that, but it's usually not what you want.

[weaknessforcats]

a basic_iostream<int, etc...> requires a traits class. Int that traits class there is a char_type and an int_type. The char_type is the type used for the stream width and the int_type is an integer that can represent any valus of char_type plus the end-of-file or EOF character.

Therefore, int_type is larger than char_type.

If your char_type is int, then what is your int_type? Like, have you written a special traits class?

[zeeshan708]

ok.thats good.now i get it.