dynamic-memory-allocation

问题 I know how to create a array of dynamic objects. For example, the class name is Stock. Stock *stockArray[4]; for(int i = 0 ; i < 4;i++) { stockArray[i] = new Stock(); } How do you change this to dynamic array of dynamic objects? What I tried: Stock stockArrayPointer = new Stock stock[4]; It doesn't work and the error is "The value of Stock** cannot be used to initalize an entity of type Stock. Second question is after the creation of dynamic array of dynamic objects, what is the syntax to

问题 This question already has answers here : Is delete[] equal to delete? (6 answers) Closed 4 years ago . I have a very quick question: What is the difference between new[ ] / delete [ ] vs new / delete in C++ when it comes to Dynamic memory? Is new[ ] / delete [ ] not belong to Dynamic memory? 回答1: new allocates memory for a single item and calls its constructor, and delete calls its destructor and frees its memory. new[] allocates memory for an array of items and calls their constructors, and

问题 I have use the code like below char *es_data; fp_input = fopen(inp_path, "rb"); fseek(fp_input, 0, SEEK_END); file_size = ftell(fp_input); fseek(fp_input, 0, SEEK_SET); es_data = (char*)malloc(file_size); fread(es_data, 1, file_size, fp_input); I have a file of 185mb, i.e., file_size = 190108334 bytes. For this file, malloc is crashing, and program is getting struck at this stage. If i use any other file of lower size, it works fine. What can I do ? 回答1: You should test at least that fopen

问题 Consider the code auto p = new T( U(std::move(v)) ); The initializer is then U(std::move(v)) . Let's assume that T( U(std::move(v)) ) does not throw. If the initializer is evaluated after the underlying memory allocation, the code is then strong-exception-safe. Otherwise, it is not. Had memory allocation thrown, v would have already been moved. I'm therefore interested in the relative order between memory allocation and initializer evaluation. Is it defined, unspecified, or what? 回答1: Yes,

问题 Has anybody used SmallObjectAllocator from Modern C++ Design by Andrei Alexandrescu in a big project? I want to implement this allocator but I need some opinions about it before using it in my project. I made some tests and it seems very fast, but the tests were made in a small test environment. I want to know how fast it is when are lots of small objects(like events, smart pointers, etc) and how much extra memory it uses. 回答1: I suggest you ask Rich Sposato. He has done extensive work on

问题 I have been taught in lectures, that calling free() on a pointer twice is really, really bad. I know that it is good practice, to set a pointer to NULL , right after having freed it. However, I still have never heard any explanation as to why that is. From what I understand, the way malloc() works, it should technically keep track of the pointers it has allocated and given you to use. So why does it not know, whether a pointer it receives through free() has been freed yet or not? I would love

问题 I have been taught in lectures, that calling free() on a pointer twice is really, really bad. I know that it is good practice, to set a pointer to NULL , right after having freed it. However, I still have never heard any explanation as to why that is. From what I understand, the way malloc() works, it should technically keep track of the pointers it has allocated and given you to use. So why does it not know, whether a pointer it receives through free() has been freed yet or not? I would love

问题 I have problem with passing array of struct to gpu kernel. I based on this topic - cudaMemcpy segmentation fault and I wrote sth like this: #include <stdio.h> #include <stdlib.h> struct Test { char *array; }; __global__ void kernel(Test *dev_test) { for(int i=0; i < 5; i++) { printf("Kernel[0][i]: %c \n", dev_test[0].array[i]); } } int main(void) { int n = 4, size = 5; Test *dev_test, *test; test = (Test*)malloc(sizeof(Test)*n); for(int i = 0; i < n; i++) test[i].array = (char*)malloc(size *

问题 I got a memory leak (55 bytes) on my program like this. I am using C++, MFC, Visual Studio 2010. Detected memory leaks! {13497} normal block at 0x0E44C248, 55 bytes long. Data: 44 3A 5C 46 44 41 53.... the problem is, the memory allocation number "13497" is not always same. it's always different number if I run the program again. I wanted to find where I didn't release the memory before the exit, with _crtBreakAlloc, but it seems not possible to break on a memory allocation number. I used

问题 I got a memory leak (55 bytes) on my program like this. I am using C++, MFC, Visual Studio 2010. Detected memory leaks! {13497} normal block at 0x0E44C248, 55 bytes long. Data: 44 3A 5C 46 44 41 53.... the problem is, the memory allocation number "13497" is not always same. it's always different number if I run the program again. I wanted to find where I didn't release the memory before the exit, with _crtBreakAlloc, but it seems not possible to break on a memory allocation number. I used