I have a nested record structure in C++ that contains a FileHeader record, a RecordHeader record and a DataRecord record. The last item is an array of unknown size (at compile time). I have to open a file and read the array size and then create the array.
I have worked on this for some time and can't figure out how to make it work. I know the sample data I am using has 85 records. I insert 85 into the array size and it works fine. But how do I create a dynamic array or define a vector within a nested structure?
1. What is the best (easiest) method to accomplish this (array or vector)? 2. How would it be implemented/how do you add data to it?
PreviousLogRecord.FaultRecord.push_back(field1); // does not work PreviousLogRecord.FaultRecord[recordNumber].field1 = somedata; // works with 85 in array size. struct LogFileHeaderRecordType { QString field1; int field2;
if we don't provide the acces modifiers for base class and we need to manipulate the private data of base class in derived class. Is there anyway to acces the private data members? Here's a coding example
class A { private : int a; }; class B : public class A { public : void displayA() { cout<<a<<endl; } };
how i can acces the a of base class A in derived class B without acces modifiers.
I am storing info in a vector but I want to store certain info at a particular index. I am new to using vectors and am unsure about have to do this. I am aware of the insert method but am confused on how to use it to store at a particular index.
What happens is, after having called the collisionDestroy-function and the program tries to execute the nest loop in the outer for-loop, it all crashes with the text "Expression: vector iterator not decrementable", which I understand is because the iterator will have already become useless. The question is: know this, how do I fix it? I can't seem to get a hang of it.
Here's the collisionDestroy-function (the collisionReaction does nothing but sets a few local variables):
void Enemy::collisionDestroy(std::vector<Sprite*>& sprites) { for (std::vector<Sprite*>::iterator iter = sprites.begin(); iter != sprites.end(); iter++) { Enemy* tmp = dynamic_cast<Enemy*>(*iter); if (this == tmp && collisionType == 3 || collisionType == 1) { sprites.erase(iter); break; } } }
And came across the following error during link stage: "/usr/include/c++/4.6/bits/stl_vector.h:1080:4: error: no matching function for call to ‘std::vector<cv::Point_<int> >::_M_fill_initialize(std::vector<cv::Point_<int> >::size_type, int&)’ "
it seems that I cannot define a method of an inner nested class if it is a private class. for example:
class outter { class nested { void foo ( void ) {} // okay - but is this inline? } void inner::foo( void ) {} // not okay - cannot define inside another class } void outter::inner::foo( void ) {} // not okay - 'nested' class is private!
what I want to know is, is there another way to define an inner class's method? and if not, is it eternally doomed to be inline because it has to be declared inside it's own class declaration?
I am having problems invoking methods in a nested class using reflection. I have the following:
A parent class, Group, that holds instances of a simple class called Signal. I want to modify the number of instances inside the group class often. So, all my code has to be dynamic and use reflection to know how many instances of signal there are inside the Group class.
class Group{ public static Signal name1 { get; set; } public static Signal name2 { get; set; } public static Signal name3 { get; set; }
[Code]....
I had no luck invoking the method of the instances of signal class that are inside the Group class. I tried getting the methods name using getMethods() but could not navigate through the syntax.
How could I invoke and pass parameters to the method of the instances of signal using reflection? Is there a better way of accessing the properties and methods of nested classes?
I have the following code which will find the minimum size queue among a vector of queues and the minimimum size queue will enqueue(push) the int
std::vector<std::queue<int> > q void enqueue(){ int min_index = 1; std::size_t size = q.size(); for( i=2; i<size; i++) //accessing loop of queues if(q[min_index].size() > q[i].size()) min_index = i; // Now q[min_index] is the shortest queue q[min_index].push(int) }
Now my another paradigm is to do the dequeue(pop) operation in another function(shown below), bt i need to access all vector of queues declared in enqueue() function. how can i access the loop of queues given in the enqueue() function?
void dequeue(){ //q.pop operation , access all the queues in the loop of queues } willq[i].pop(int);
Access all the queues in the enqueue function and does the pop operation?
So I have an ImageManager class, Board class, and Box class. In Board.h I can declare ImageManager imgr; and in Board's constructor I can use imgr and its functions and such. However, in Box.h when I try and declare ImageManager imgr; I get the error "cannot access member declared in class ImageManager". Both declarations are under private, and exactly the same, but one doesn't work. Also, is there a way to only have one instance of ImageManager?
I have two classes, a Package class and a Person class. The Package class has two Person objects has member variables, a Sender and a Receiver. While overloading the << operator for the Package class so that it will make an output label from everything in the Package class. Here is my code...
class Package{ public: Person Sender; Person Reciever; int weight; double cost; friend ostream &operator<<(ostream &out, Package &pack);
[Code] .....
So my problem is on that last output line, I am unable to call Sender.getName()... etc. Is there a proper syntax so that I can access the members of the Person class while overloading the << operator for the Package class?
I need to access the functions of the derived classes from a vector of objects of base classes (can't believe I wrote it). Here a Diagram for you to understand:
So as you see, I need the function Use() from the Usable class, to be able to be called from the vector like:
"A nested class has free access to all the static members of the enclosing class. All the instance members can be accessed through an object of the enclosing class type, or a pointer or reference to an object."
How can the members be accessed through an object of the enclosing class type? I understand the pointer and reference part because for them you dont need the full definition, but for creating a object you do?
Also it has free access to all static members because the nested class is part of the enclosed class and with static it exists in everything inside the enclosing class? Right or am I missing something?
