Comments on: 9.5 — Overloading unary operators +, -, and ! http://www.learncpp.com/cpp-tutorial/95-overloading-unary-operators/ Mon, 13 Oct 2008 11:26:28 +0000 http://wordpress.org/?v=2.5.1 By: davidv http://www.learncpp.com/cpp-tutorial/95-overloading-unary-operators/#comment-27500 davidv Tue, 16 Sep 2008 03:25:59 +0000 http://www.learncpp.com/cpp-tutorial/95-overloading-operators-and/#comment-27500 <pre> if (nX) // do something </pre> should be <pre> if (!nX) // do something </pre> [ Fixed! Thank you. -Alex ] if (nX) // do something

should be


if (!nX)
    // do something

[ Fixed! Thank you. -Alex ]

]]> By: Learn C++ - » 9.4 — Overloading the comparison operators http://www.learncpp.com/cpp-tutorial/95-overloading-unary-operators/#comment-14404 Learn C++ - » 9.4 — Overloading the comparison operators Mon, 05 May 2008 02:04:24 +0000 http://www.learncpp.com/cpp-tutorial/95-overloading-operators-and/#comment-14404 [...] 2007 Prev/Next Posts « 9.3 — Overloading the I/O operators | Home | 9.5 — Overloading unary operators +, -, and ! » Thursday, October 4th, 2007 at 5:10 [...] [...] 2007 Prev/Next Posts « 9.3 — Overloading the I/O operators | Home | 9.5 — Overloading unary operators +, -, and ! » Thursday, October 4th, 2007 at 5:10 [...]

]]> By: Alex http://www.learncpp.com/cpp-tutorial/95-overloading-unary-operators/#comment-11804 Alex Tue, 15 Apr 2008 18:21:32 +0000 http://www.learncpp.com/cpp-tutorial/95-overloading-operators-and/#comment-11804 I think you could do this via overloading typecasts. If you provide an overloaded boolean conversion operator for your point, then I think the above example would work. This is covered in lesson <a href="http://www.learncpp.com/cpp-tutorial/910-overloading-typecasts/" rel="nofollow">9.10</a>. However, personally I wouldn't recommend implementing it this way. The conversion from point to boolean isn't very intuitive. I think this is better implemented as a member function that returns a boolean result -- in this way, your code will be more self-documenting. eg: <pre> if (cPoint.IsOrigin()) // etc </pre> I think you could do this via overloading typecasts. If you provide an overloaded boolean conversion operator for your point, then I think the above example would work. This is covered in lesson 9.10.

However, personally I wouldn’t recommend implementing it this way. The conversion from point to boolean isn’t very intuitive. I think this is better implemented as a member function that returns a boolean result — in this way, your code will be more self-documenting. eg:

if (cPoint.IsOrigin())
    // etc
]]> By: Shaun http://www.learncpp.com/cpp-tutorial/95-overloading-unary-operators/#comment-11705 Shaun Mon, 14 Apr 2008 12:45:40 +0000 http://www.learncpp.com/cpp-tutorial/95-overloading-operators-and/#comment-11705 Is there an operator I can use to overload the usual if() effect? E.g., <pre> if (cPoint) cout << "cPoint is not at the origin." << endl; else cout << "cPoint is at the origin." << endl; </pre> What would happen in this case? Would C++ call the ! operator and reverse the result? Or is there another way to provide a boolean operator? Is there an operator I can use to overload the usual if() effect? E.g.,

if (cPoint)
    cout < < "cPoint is not at the origin." << endl;
else
    cout << "cPoint is at the origin." << endl;

What would happen in this case? Would C++ call the ! operator and reverse the result? Or is there another way to provide a boolean operator? ]]>