Because SO is a bit slow lately, I'm posting an easy question. I would appreciate it if big fishes stayed on the bench for this one and give rookies a chance to respond. Sometimes we have objects that have a ridiculous amount of large list elements (vectors). How would you "unlist" this object into a single vector. Show proof that your ...
hello, when i use vector to store some data, i usually access to this data by the pointer of the vector's first entry. because it it faster than the at() method. but i realize that when i insert a block of data, say an array to the end of vector, the first entry's pointer changes. this may be realated to stack stuff, but if i add the ar...
I have a row-vector with arbitrary values. I am interested in the column IDs of the columns which contain a value <= a specified threshold the number of columns which lie below the threshold. Is there a more elegant way to compute this in MATLAB than using a for-loop? ...
Reviewing for midterm, need some help with the following: Given the points p0 = [1 0] and p1 = [4 6] write the implicit equation for a line in vector form (i.e. compute the appropriate v and n). Is the point p2 = [1.5 3] on the line or above or below the line? What is the equation for a plane with the norman n = [5 3 4] going through t...
Hello, I would like to do the following in Java: I have an element, and I would like to know what would be its index had it been inserted into a collection of other objects (given they're already sorted). So if I have a vector of ints like this: 1,3,5,7,9 and I had the int '2' in hand, I'd know that its 'would-be' index is i=1, between...
Hi, just came a across a situation where I needs to store heap-allocated pointers (to a class B) in an STL container. The class that owns the privately held container (class A) also creates the instances of B. Class A will be able to return a const pointers to B instances for clients of A. Now, does it matter if these pointer are stor...
What is the easiest way to take something out of an vector and changes its values? This isn't working the way I expected. for(int i = 0; i < list.size(); i++) { someType s = list.at(i); s.x = 10; s.y = 20; s.z = 30; } However, when I go to print out the x,y,z of that someType s, it doesn't give me what I expect. Sorry I am mixing up ...
Hi, I'm coding a flocking algorithm in Java but I'm stuck at a certain point (using the Ardor3D libraries, in a 2D plane). Basically, I need to find the angle difference to add to the current rotation. If you can only get the way it should be pointing with polar coordinates with 0 degs at north and not the difference, not to worry -- I ...
Generally, I would use boost::mpl::for_each<>() to traverse a boost::mpl::vector, but this requires a functor with a template function declared like the following: template<typename T> void operator()(T&){T::staticCall();} My problem with this is that I don't want the object T to be instantiated by for_each<>. I don't need the T parame...
Hi, I'm simulating a physical object, using a mass spring system. By means of deltas and cross products, I can easily calulate the up, forward and side vectors. I want to calculate what the angular rate (how fast it's spinning), for the object space X, Y and Z axis. Calculating the world space angle first won't help, since I need the a...
This compiles and runs ok on Visual C++ 2010 Express but it only checks against the [2] element: "Fish". int main() { vector<string> words; string temp; vector<string> disliked(3); disliked[0] = "Broccoli"; disliked[1] = "Mushrooms"; disliked[2] = "Fish"; while (cin >> temp) ...
Hi Guys, How to pass a 2 dimensional Vector to a function in CPP ? I saw the examples for 1 dimension but not for 2 dimensions. If it is passed, is it passed by value or by reference ? vector< vector<int> > matrix1(3, vector<int>(3,0)); //Matrix Declaration. printMatrix(&matrix1); // Function call void printMatrix(vector< vector<int...