What I mean is – we know that the std::map‘s elements are sorted according to the keys. So, let’s say the keys are integers. If I iterate from std::map::begin() to std::map::end() using a for, does the standard guarantee that I’ll iterate consequently through the elements with keys, sorted in ascending order? Example: std::map<int, int> map_; … Read more
Are there any advantages of std::for_each over for loop? To me, std::for_each only seems to hinder the readability of code. Why do then some coding standards recommend its use? 22 Answers 22
Is there a built-in vector function in C++ to reverse a vector in place? Or do you just have to do it manually? 7 Answers 7
Why does the reverse function for the std::list class in the C++ standard library have linear runtime? I would think that for doubly-linked lists the reverse function should have been O(1). Reversing a doubly-linked list should just involve switching the head and the tail pointers. 7 Answers 7
Is there any code to find the maximum value of integer (accordingly to the compiler) in C/C++ like Integer.MaxValue function in java? 8 Answers 8
What are the pros and cons of using Qt containers (QMap, QVector, etc.) over their STL equivalent? I can see one reason to prefer Qt: Qt containers can be passed along to other parts of Qt. For example, they can be used to populate a QVariant and then a QSettings (with some limitation though, only … Read more
I am using std::queue for implementing JobQueue class. ( Basically this class process each job in FIFO manner). In one scenario, I want to clear the queue in one shot( delete all jobs from the queue). I don’t see any clear method available in std::queue class. How do I efficiently implement the clear method for … Read more
Are all of the following statements true? vector<Type> vect; //allocates vect on stack and each of the Type (using std::allocator) also will be on the stack vector<Type> *vect = new vector<Type>; //allocates vect on heap and each of the Type will be allocated on stack vector<Type*> vect; //vect will be on stack and Type* will … Read more
I’m reading STL source code and I have no idea what && address operator is supposed to do. Here is a code example from stl_vector.h: vector& operator=(vector&& __x) // <– Note double ampersands here { // NB: DR 675. this->clear(); this->swap(__x); return *this; } Does “Address of Address” make any sense? Why does it have … Read more
Let’s say you’ve got an airplane, and it is low on fuel. Unless the plane drops 3000 pounds of passenger weight, it will not be able to reach the next airport. To save the maximum number of lives, we would like to throw the heaviest people off of the plane first. And oh yeah, there … Read more
