new-operator

问题 I have overloadded operator new[] like this void * human::operator new[] (unsigned long int count){ cout << " calling new for array with size = " << count << endl ; void * temp = malloc(count) ; return temp ; } and now calling human * h = new human[14] ; say sizeof(human) = 16 , but count it prints is 232 which is 14*16 + sizeof( int * ) = 224+8 . Why is this extra space being allocated ? And where does it fall in memory ? Because when I print *h OR h[0] I get same results , so its not in

问题 If I have the following statement: int *x = new int; In this case, I have allocated memory on the heap dynamically. In other words, I now have a reserved memory address for an int object. Say after that that I made the following: delete x; Which means that I freed up the memory address on the heap. Say after that I did the following again: int *x = new int; Will x point to the same old memory address it pointed to at the heap before it was deleted? What if I did this before delete : x = NULL;

问题 This is a follow-up question to What is wrong with this code that promisify a function? Method 1 works; var Converter = require('csvtojson').Converter; Promise.promisifyAll(Converter.prototype); var converter = new Converter(); Method 2 does not work; var Converter = require('csvtojson').Converter; var converter = Promise.promisifyAll(Converter.prototype); Why does method 1 work and not method 2? 回答1: Promise.promisifyAll(obj) returns obj , therefore ... Promise.promisifyAll(Converter

问题 My aim was to simply make a hangman game. However, I have been slightly over-ambitious. I want to ask the user to input how long they want the word. Then choose a random word of that length. To index an entire dictionary of that length would take far too long on each iteration. So. I have a dictionary, formatted like so: zymosans zymoscope zymoses ... I would like to be able output a file for each 'length of word' automatically using this program. Like this: 1letterwords.txt 2letterwords.txt

问题 Please check this code out it compiles and runs absolutely fine.. The question is that when i started learning c++ (turbo c++) i never was able to declare an array of any type as .. datatype var[variable_set_at_runtime]; and i took it for granted that this cant be possible in latest gcc compilers...but surprisingly this is possible... So my related question is that whats the need of new operator then?? I know that new operator does a lot of things including dynamically allocating memory at

问题 In the middle of Mozilla documentation page it switches (without clear enough explanation) examples from WorkerBee.prototype = Object.create(Employee.prototype); to WorkerBee.prototype = new Employee; Second form new Employee will initialize prototype of WorkBee with properties that are supposed to exist only in instances of WorkBee. Why is second form being used in so many examples of JavaScript inheritance ? Isn't it undesired to give different status to inherited properties vs own

问题 In the middle of Mozilla documentation page it switches (without clear enough explanation) examples from WorkerBee.prototype = Object.create(Employee.prototype); to WorkerBee.prototype = new Employee; Second form new Employee will initialize prototype of WorkBee with properties that are supposed to exist only in instances of WorkBee. Why is second form being used in so many examples of JavaScript inheritance ? Isn't it undesired to give different status to inherited properties vs own

问题 I defined a class foo as follows: class foo { private: static int objcnt; public: foo() { if(objcnt==8) throw outOfMemory("No more space!"); else objcnt++; } class outOfMemory { public: outOfMemory(char* msg) { cout << msg << endl;} }; ~foo() { cout << "Deleting foo." << endl; objcnt--;} }; int foo::objcnt = 0; And here's the main function: int main() { try { foo* p = new foo[3]; cout << "p in try " << p << endl; foo* q = new foo[7]; }catch(foo::outOfMemory& o) { cout << "Out-of-memory

问题 What is difference between new and new[1] ? Can I use delete with new[1] ? Edit Well well well, I should've provided the background, sorry for that. I was evaluating BoundsChecker at work with VS 2010 and it complained about a memory leak when I used delete[] on new[1]. So in theory I know how the new and delete pair should be used but this particular situation confused me about the things under the hood. Any idea whats happening? 回答1: Ed and aix are right, but there is much more going on

问题 Which is the right way to allocate memory via new in the C++ constructor. First way in the argument list: class Boda { int *memory; public: Boda(int length) : memory(new int [length]) {} ~Boda() { delete [] memory; } }; or in the body of constructor: class Boda { int *memory; public: Boda(int length) { memory = new int [length]; } ~Boda() { delete [] memory; } }; Thanks, Boda Cydo. 回答1: I think the simplest way to do this would be to use a boost scoped array and let someone else's well tested