erase

问题 In C++, how can I delete an element from a vector? Delete it right from where it is, i.e. let the vector resize Swap the element to be deleted with the last element s.t. pop_back() can be used (which I hope doesn't involve copying everything around...) For (1), I've tried the following, but I'm not quite sure if it does what it is supposed to do (remove the item passed to removeItem() ), and it doesn't seem very elegant: vector<Item*> items; // fill vector with lots of pointers to item

问题 Here is the code for Drawing and Undoing but unable to join with Erasing. It is either Drawing + Erasing or Drawing + Undoing but cannot three of these. public class Drawing extends View { private Paint mPaint, mBitmapPaint; private Bitmap mBitmap; private Canvas mCanvas; private Path mPath; private float mX, mY; private static final float TOUCH_TOLERANCE = 4; private int color, size, state; private ArrayList<Path> paths = new ArrayList<Path>(); private ArrayList<Path> undonePaths = new

问题 I'm trying to figure out how to "cut-out a feathered hole" in an ImageView. The reasoning is, I am creating a tutorial, and I want the whole screen dim. That's easy enough to do by placing a black image with alpha around 50%. Next I want to cut a hole into that overlay, so you can more clearly see what's underneath it. The goal in mind is to highlight buttons and things for the user to click on, so they learn what to do. When I did this before in ActionScript / Flash, it was easy to just put

问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed last year . Here is my code: #include <iostream> #include <string> #include<bits/stdc++.h> using namespace std; int main() { int n; cin >> n; while(n--) { string str; char a[] = {'a','e','i','o','u','A','E','I','O','U'}; getline(cin, str); for(int i=0 ;i<str.length(); i++) { for(int j=0; j<10; j++) { if(str[i]=

问题 New in image editing.. i want to develop an app like https://play.google.com/store/apps/details?id=com.outthinking.bgeraser and looking for main functionality which is removing background of any image help me... Thanks in advance.. 回答1: I guess your problem is, that you don't exactly know what you are looking for. Just search for: Background Subtraction Thats how it is called. You can find lots of articles about that. Come back if you have more detailed questions. 来源： https://stackoverflow

问题 I have a simple for loop: for (int i = 0; i < c.numparticles; i++) { if ( labs((noncollision[i].getypos())) > 5000 ) { noncollision.erase (noncollision.begin()+i); } } Where noncollision is a vector of class particle . In this specific example, any noncollision which has a ypos greater than 5000 should be erased. I have been working with a noncollision size of 6, of which 2 have ypos much greater than 5000. However, this for loop is only erasing one of them, completely ignoring the other. My

问题 I know that this question is similar to others, but I looked here and here and neither of these solved my problem. Everything I have been able to find says that the following code should work. The vector I use for testing has elements with names superman, batman, and spiderman. I can't remove any more code for the example to make sense I don't think. class Room{ vector<User> users; users = {{superman, pass}, {batman, pass}, {spiderman, pass}}; public: vector<User> Room::getUsers() {return

问题 I'm working with a MCF51EM256 Freescale microcontroller and I've some problems to store data in the external flash memory to make it persistent. I need to store this struct: typedef struct { ui64_s Ea_ps; ui64_s Ea_ng; ui64_s Er_q1; ui64_s Er_q2; ui64_s Er_q3; ui64_s Er_q4; uint16 F_ea; uint16 F_er; }Ws_EnergyAcc64; Where: typedef union{ uint64 v; uint32 p[2]; } ui64_s; and: typedef unsigned long long int uint64; typedef unsigned long int uint32; typedef unsigned short int uint16; In order to

问题 Page http://www.cplusplus.com/reference/vector/vector/erase/ says Linear on the number of elements erased (destructions) plus the number of elements after the last element deleted (moving). So, if I am deleting an element, say, with index j from vector of some length n (n>j) - will it be constant or linear(O(n))? Or, if I have p elements after Jth element, then it will be of order O(p) - am I right? 回答1: From the link you provided: Linear on the number of elements erased (destructions) plus

问题 I have a vector and I would like to efficiently break out the second half of the vector into another vector using STL algorithms. Here is one way I see to do this, but expect there are more efficient and succinct answers, or at the least, one that uses the stl algorithms: std::vector<Entry> &entries = someFunction(); int numEntries = entries.size(); // Assume numEntries is greater than or equal to 2. std::vector<Entry> secondEntries; std::vector<Entry>::iterator halfway = entries.begin() +