Defining operators

I recently learned how to declare types ex. time_t

like
typedef long double n_type;

How do you create operators?
in iostream the redefined << and >> for cout and cin (god know's why?)
how do I make new operators.

oh and also I am looking for a website on understanding header files because my friend is also learning and I can't explain it RIGHT. So I am looking for material in that are too.

Any help would be appreciated.

Look up operator overloading

http://www.cplusplus.com/doc/tutorial/tut4-2.html

>(god know's why?)
Why? What if you have a class that you would like to print directly with cout?

Code:

#include <iostream>

class Test
{
  int i, j;
public:
  Test ( int one, int two ) :
    i ( one ), j ( two )
  {}
};

int main()
{
  Test t ( 10, 20 );

  std::cout<< t <<std::endl;

  return 0;
}

This will obviously not work because cout isn't defined for objects of class Test. You need to define it yourself:

Code:

#include <iostream>

class Test
{
  int i, j;
public:
  Test ( int one, int two ) :
    i ( one ), j ( two )
  {}
  friend std::ostream& operator<< ( std::ostream& os, const Test& t )
  {
    os<< t.i <<" -- "<< t.j;
    return os;
  }
};

int main()
{
  Test t ( 10, 20 );

  std::cout<< t <<std::endl;

  return 0;
}

Now everything works just peachy.

-Prelude

I think L-P was questioning the use of the shift left and shift right operators as insertion operators. That's a reasonable concern but not something that matters a whole lot. I will frequently overload the [] operators but others are more rare.