prefix-operator

Defined this way, we can do neither ++x++ nor ++x-- . But on the other hand, both (++x)++ and (++x)-- are useful expressions: (++x)++ increments x by two and returns the value "in the middle", while (++x)-- is essentially equivalent to x+1 but completely avoids having to call operator+ , which can be quite useful sometimes. So why is the precedence not defined to have ++x++ automatically expand to (++x)++ rather than ++(x++) ? Is there some hidden meaning to the latter which I don't understand, or is it just to keep the precedence a simple list with all prefix operators making up one single

Currently I'm teaching a class of C++ programmers the basics of the C# language. As we discussed the topic operators I used C# standard categories of primary, unary etc. operators. One of the attendees felt puzzled, because in the C# standard the "postfix ++/--" have been put in the category of primary operators rather than the "prefix ++/--". Her rationale behind this confusion was, that she would rather implement the C++ operator "postfix ++/--" in terms of the operator "prefix ++/--". In other words she would rather count the operator "prefix ++/--" as a primary operator. - I understand her

By mistake, I wrote: ++number++; and got this: Uncaught ReferenceError: Invalid left-hand side expression in prefix operation Why? I would except this to to first increment number by one and then increment number by one again. In JavaScript, ++ is both the prefix and postfix increment operator. The postfix operator has higher precedence, and so when we apply precedence, your expression becomes: ++(number++); The result of number++ is a value, not a variable reference, and so it cannot be the operand of the prefix increment operator, for the same reason ++42 is invalid — there's nowhere to

please consider following code #include <iostream> using namespace std; class Digit { private: int m_digit; public: Digit(int ndigit=0){ m_digit=ndigit; } Digit& operator++();//prefix Digit& operator--(); //prefix Digit operator++(int); Digit operator--(int); int get() const { return m_digit;} }; Digit& Digit::operator++(){ ++m_digit; return *this; } Digit& Digit::operator--(){ --m_digit; return *this; } Digit Digit::operator++(int){ Digit cresult(m_digit); ++(*this); return cresult; } Digit Digit::operator--(int){ Digit cresult(m_digit); --(*this); return cresult; } int main(){ Digit cDigit(5

I have this piece of code (taken from this question ): var walk = function(dir, done) { var results = []; fs.readdir(dir, function(err, list) { if (err) return done(err); var pending = list.length; if (!pending) return done(null, results); list.forEach(function(file) { file = path.resolve(dir, file); fs.stat(file, function(err, stat) { if (stat && stat.isDirectory()) { walk(file, function(err, res) { results = results.concat(res); if (!--pending) done(null, results); }); } else { results.push(file); if (!--pending) done(null, results); } }); }); }); }; I'm trying to follow it, and I think I