pointers

问题 In Visual Studio 2008, is there a way of finding all the variables that point to the same object as another variable? So in the example below I would want to find out that ref1 and ref2 both point to the same object as original . var original = new List<string>() { "Some Data" }; var ref1 = original; var ref2 = ref1; Essentially I want to be able to call ReferenceEquals() on all the variables in memory and then see all the ones that are equal. Except I want to be able to do this in the VS2008

问题 Hello there I've been struggling with this problem for some time and after some research on the internet that didn't bear any fruit I decided to ask for some help. I need to read some integers from a file and from a specific line and then do something with them. I know this trick for handling strings of characters while(fgets(pointer_to_string, length, "file_name.txt")) line++; /*increment line-integer type- by 1*/ if(line == your_line) /*do something with the strings at that line*/ I know

问题 I need to create an instance in class Crop of Plant class and i cant manage to find a way to make that work. Hope you guys can help at that. This my main where i'm sending an object to the class crop. int main(){ char select = 'a'; int plant_num = 2; int crop_num = 0; Crop crop[10]; Plant plant[20]; plant[0] = Plant("Carrots",'c'); plant[1] = Plant("Lettuce",'l'); plant[2] = Plant("Rosemary",'r'); crop[0] = Crop(plant[0],4,2); crop_num++; cout << "Garden Designer" << endl; cout << "==========

问题 This is a follow up to this question: Having a function change the value a pointer represents in C As an exercise, I am trying to make a generic function that changes a value in an array of undetermined type. I guess it should look like that. void set_value(void * data, void * value, size_t size, int index){ void * position = data + index*size; *position = *value; } Of course that does not compile, *position = *value do not use the information of the size of value (here was assume both data

问题 I am currently studying C language. I wonder what 'array decaying' means, and when it happens. And I wonder if the two variables below are interpreted in the same way. char(*zippo)[2] = NULL; char zippo2[4][2]; zippo = (char(*)[2])malloc(sizeof(char[2]) * 4); 回答1: From the C Standard (6.3.2.1 Lvalues, arrays, and function designators) 3 Except when it is the operand of the sizeof operator or the unary & operator, or is a string literal used to initialize an array, an expression that has type

问题 In the following code var a int var b interface{} b = a fmt.Printf("%T, %T \n", a, &a) fmt.Printf("%T, %T \n", b, &b) output: int, *int int, *interface {} I would expect the type of &b to be a pointer on int. I have two questions: 1) Why is it a pointer on interface{} ? 2) How could I get a pointer on the original type ? 回答1: &b => this is the address operator applied on the variable b , whose type is interface{} . So &b will be a pointer of type *interface{} , pointing to the variable b . If

问题 This may be a dumb question but I don't understand why do I get this error : void func (int ** array) { } int main (void) { int array[5][5] = { }; func(array); } warning: passing argument 1 of 'func' from incompatible pointer type [-Wincompatible-pointer-types] func(array); ^~~~~ note: expected 'int **' but argument is of type 'int (*)[5]' void func (int ** array) { } ~~~~~~~^~~~~ 回答1: Consider a function void foo(int **p) . The p it is given contains some address. At that address, there is

问题 This question already has answers here : Why can't we use double pointer to represent two dimensional arrays? (5 answers) usage of double pointers as arguments (4 answers) Closed 6 years ago . This is a sample code of my program. I have a function named function which is used to return an integer value and an integer array. I have to pass them as pointers (The signature of function cannot be changed). So I wrote the below code. Here I have to assign the values to the double pointer passed to

问题 I'm creating a system that uses multiple cursors (pointers) in multiple xsessions. My computer has multiple video cards in it for controlling different monitors. I want to have a different cursor on each screen and control each. Each monitor is a different session. I started using the xlib library in C to control the single cursor I have using the following command: XWarpPointer(display,None,window,0,0,0,0,x,y); This works perfectly for one cursor. Then I created a second cursor using xinput

问题 This is mainly a question about scope and threads. Let's say we have the following struct. struct Test { int number; std::string name; }; An instance of this struct will be used as an argument in the pthread_create function. Here is an example of what this might look like. pthread_t tid[5]; for(int i = 0; i < 5; ++i) { Test test; test.number = 5; test.name = "test"; pthread_create(&tid[i], NULL, func, (void *)&test); } Is this acceptable? Since test is declared in the for's scope, that means