reference

问题 So I want to pass a pointer to a function and have that function modify that pointer from inside that function. How do i do that in general? In here? EDIT: Since the treeNode is a struct of pointers I want to take nodePtr->vendorDataRef inside of the removeLeftMostNode(...) function and somehow get it back to the calling function. I thought I could do this through a parameter of removeLeftMostNode(...) hence removeLeftMostNode(...aVendor* vendorDataRef) i.e. aBst::treeNode * aBst::removeNode

问题 Hy everyone, pls consider this small code, and help me to figure out, why it's not working? #include <stdio.h> #include <stdlib.h> void setup(int* helo) { helo = (int*) malloc(sizeof(int)); (*helo) = 8; } int main(int argc, char* argv[]) { int* helo = NULL; setup(helo); printf("Value: %s \n", (*helo)); getchar(); return 0; } 回答1: You are looking for one of two options here. You can either take the memory pointer allocation out of the equation, and pass the memory address of a standard

问题 This question already has answers here : Closed 9 years ago . Possible Duplicates: When pass-by-pointer is preferred to pass-by-reference in C++? Are there benefits of passing by pointer over passing by reference in C++? How to pass objects to functions in C++? Hi all, I'm working to develop a large object oriented c++ application framework as part of my chemical engineering graduate research. I find that many of my functions take pointers to custom objects or STL objects. I find that in

问题 Experimenting with this question/answer https://stackoverflow.com/a/50649120/225186 I produced what seems to be a legal recursive self referential class that implements a circular list: struct node{ int val; node const& next; }; int main(){ node s{3, {4, s}}; assert(s.val == 3); assert(s.next.val == 4); assert(&s.next.next == &s); assert(s.next.next.val == 3); } However, when I try put this as a member of a larger class I get a warning from the compiler and the behavior changes. struct A{

问题 Is it possible to make a class that is not a struct but is a value type, or is like a value type in that it copies on being passed instead of being passed by reference. edit: Sorry about the question having to be edited after being asked. Also, see this question for more information. Cycle in the struct layout that doesn't exist 回答1: EDIT 2 As it now seems, you're looking to declare a true value type using the class keyword, which is by definition not possible. Since you're looking at

问题 I would like to create a list or map of references in C++ which automatically deletes its elements upon their destruction. Here is a structure demonstrating the idea. class Foo; class Bar { Foo foo; }; void main(void) { std::vector<Foo> foos; { Bar bar; foos.push_back(bar.foo); // foos[0] should be the same reference as bar.foo } // bar is now destructed // foos.size() should be 0 } There are two things wrong with my code. When push_back() is called with a std::vector, it creates a copy of

问题 Example code: testClass1.pm package testClass1; { my $testClass2Ref; sub new { my($class) = shift; $testClass2Ref= shift; bless $self, $class; return $self;} } sub testRef { $testClass2Ref->testRef; } } testClass2.pm package testClass2; { sub new { my($class) = shift; bless $self, $class; return $self;} } sub testRef { print "Test 2"; } } test.pl use testClass1; use testClass2; my $testClass2 = testClass2->new(); my $testClass1 = testClass2->new($testClass2); $testClass1->testRef; When I try

问题 I have been working on an asp.net/C# website for a while and decided to put my SQL C# code into a class library (.dll). The problem is, when I try to add it to my website application in vs2010 it sees it, but doesn't at the same time. What I mean is the web application tells you that it is added as a reference under the reference folder, but when compiling the code it will say you don't have the reference. The way I add the reference is by right clicking the solution and selecting "add

问题 I am relatively new to Perl. I have a reference to an array called $TransRef that contains references to arrays. My goal is to write a sub that takes the $TransRef arguement as its only argument, sorts the references to the underlying array by the 2nd element (a string) and sets the output back to the $TransRef reference. Can someone please show how this can be done in Perl? Here is some code that generates $TransRef. It has not been tested yet and may have some bugs: # Parse the data and

问题 For example, I have an ArrayList: ArrayList<Animal> zoo = new ArrayList<Animal>(); // some code to add animals to zoo I want to create a copy of this old zoo to new zoo , and I can use remove/add... to process this new zoo.(and of course, it will not affect to old zoo). So, I have a way that: create new zoo that clone each animals in old zoo (it means create animal objects). So, it too SLOW. I have an another way: create a reference of each animals of old zoo and copy to new zoo. So, new zoo