I'm new to C++ especially vectors.. I've a question regarding sorting of object in a vector.. My object consists of x,y and civ. so I would like to know how do I sort the value of the civ in an descending order but at the same time retaining the value of x and y attached to it..
I'm implementing kruskal's algorithm and ran into some troubles compiling. I need to sort a vector of objects by value. Here is my code and the error I'm getting.
Code:
These are the two functions in graph.cpp (there are more but are unrelated)
#include <vector> #include <algorithm> #include <iostream> using namespace std; #include "graph.h" #include "edge.h" using std::vector; void graph::sort_edgesArray() {
[code].....
//This is the error I'm getting.
graph.cpp: In member function "void graph::sort_edgesArray()": graph.cpp:39:33: error: no matching function for call to sort (std::vector<edge>::iterator&, std::vector<edge>::iterator&, <unresolved overloaded function type>) /usr/include/c++/4.5/bits/stl_algo.h:5236:18: note: candidate is: void std::sort(_RAIter, _RAIter, _Compare) [with _RAIter = __gnu_cxx::__normal_iterator<edge*, std::vector<edge> >, _Compare = bool (graph::*)(edge&, edge&)]
Suppose I have a two-dimensional stl vector (a vector of vectors), for example:
Code : vector<vector<int> > x;
And then I want to sort the outer vectors in order of the size of their inner vectors. How do I do this?
Usually, with a one-dimensional vector, I can just create a comparison function and use the sort function. For example, if my vector is defined as:
Code: vector<int> y;
And I want to sort if in terms of the int values of each vector element, then I can sort by using the stl::sort function, with the comparison function defined as:
I'm trying to write a program that reads in from a .txt file the movie title, rating, director, actors etc. All I want to do is to just sort movie titles alphabetically and print all its attributes(director, actors). I tried using sort( movies.begin(), movies.end()) method, but it doesn't work.
writing a sorting function that has an argument for a vector of ints rather than an array; it should use a selection sort algorithm.Here is what I have:
#include <iostream> #include <vector> #include <conio.h> using namespace std; void fillVector(vector<int> &aVector); // PRECONDITION: number declared size of array a. // POSTCONDITION: number_used is the number of values stored in a //a[0] through a[number_used-1] have been filled with nonnegative int.
I am trying to to pull data from a file into a vector, then calculate different statistics from said vector. I've got everything working great except for one part. The program requires the median be calculated, which means I need to sort the data in the vector. However I can't do a quick easy sort, I'm required to use the functions swap(double, double), sort(vector), and index_of_smallest.
how to get these all working in sync to calculate the median(not to mention my algorithms appear to be wrong as I return nothing but 0's for the median value.)
I'm either not sorting right, or the index_of_smallest function is supposed to be doing something I don't realize.
#include <iostream> // for screen and kbd io #include <iomanip> #include <fstream> // file io #include <cstdlib> // for exit() #include <cmath> // for sqrt #include <string> #include <vector> using namespace std; void fill_vector(ifstream& in_file,vector<double>& v);
I am trying to use std::sort to sort a vector of complex objects using a custom function. However, it keeps erroring "Unresolved overloaded function type".
encounter::encounter(){ // ... cut std::sort (allpeople.begin(), allpeople.end(), sortByInit);} bool encounter::sortByInit (character& a, character& b) { if (a.getinit () == b.getinit ()) {
I tried to sort a large numbers of vector of random integers with std::sort(), but when the number increases over 10M, std::sort returns all zero in values. Does std::sort have a limitation of input numbers?
I'm trying to use a priority queue sorting in reverse order to take a vector or 2d array. The problem is that I want to sort by the vector/array cell value but keep the reference to the vector/array index of the value. I don't know quite howto keep them both related so when I pop. I can find the corresponding cell.
I am erasing a object from the vector. I want to know that do i need to delete the object before I call the erase method or calling the vector erase method is suffice. See the following example.
Class A { int val; };
Class B { vector<A *> vectorA; void AddA(int val) { A *a = new A; a->val = val; vectorA.push_back(a);
[Code] ....
I don't know which DeleteVectorEntry to use which makes sure that there is no memory leak in my program.
I'm working on collision detection for a game in SFML. I successfully designed a Spatial Partition grid to speed up the collision test, in the following of this tutorial: [URL] ....
But now I have an issue with one aspect of it: Going through a vector of objects and testing all the OTHER objects in the vector against said object. The author puts it into psueudocode here:
For each tick of the clock
For every object in the game
Get all the other objects in the same grid square
For each other object in the same grid square
I have trouble with the last line, because in iterating through a vector I am not sure how to skip over the current object. Here is my own code (a couple of sysntax errors but this is a c++ question not an SFML question):
//for every moveable object for(int i = 0; i < rects_.size(); i++){ std::vector<sf::RectangleShape> posibleObjects_; //this will be a vector of WorldObjects in a real game //for every object in that object's gridsquare for(int j = 0; j < rects_.size(); j++){ if(rects_[i].intersects(rects_[j])){ //collision } } }
The problem is, a collision will always be reported because somewhere in the vector the object will eventually check against itself which is always a true collision. What is the correct way to do this?
case DELETE_TITLE: std::cout << "Game to remove from list: "; std::cin.ignore(); getline(std::cin, gameTitle); for (iter = gameList.begin(); iter != gameList.end(); ++iter) {
[code]....
It deletes the text from the string but not the index it self.
It deletes the text but when I print the list of game titles it has it there blank. I want it to completely remove the object from the vector from where it was deleted
// objects to hold results, row id, and name class result_holder { public: // initialize class members result_holder() : row_id(0), row_value(0.0), row_name("") { }
[Code] ....
There are cases where I need to find an object based on the value of row_id and delete the object from the vector row_results. I could find the proper object by looping through the vector and testing against each member.
Code: // id I am looking for unsigned int id_to_delete = 12; for(i=0; i<row_results.size(); i++) { if(id_to_delete == row_results[i].row_id) { delete row_results[i]; } }
I have used find before to find the position in a vector with a specific value, but I don't know how to use find to locate a specific value for an object member.
Also, is delete what I need to get rid of the object or should I be using erase as in,
Code: // id I am looking for unsigned int id_to_delete = 12; for(i=0; i<row_results.size(); i++) { if(id_to_delete == row_results[i].row_id) { row_results.erase(row_results.begin()+i); } }
I'm working on a grocery store inventory project. One part is to have a shopping cart, where customers can put in up to 20 items. Because there can be up to 20 shopping carts at one time, I want to use a vector inside the cart object to represent all the individual food items.
Here's my code,
Header:
#ifndef CART_H #define CART_H #include <vector> class Cart { public: Cart(); Cart(std::vector< int >, std::vector< int >)
I know if i will not use the pointer base class function "virtual double grossPay" will be called for both base class object and derived class object and when i will use pointer with reference to the object because base class function is virtual it will look for same function in derived class and if available it will execute it.
will copy constructor does object initialization using another already created object? I understand that it can be applied for object initialization and not for assignment.Is it correct?
I have a method to take a Tile object and make an instances of it based on some data from the original object. Than it is suppose to manipulate the a specific instance and save the results. The first loop through it works but it changes all instance as well as the base.
public static int recurse(int count, Tile[,] b,Huristic h,int check) { if (check==1) { boardState.Add(B)/>; return check; } if (check == 0)
this function will return a temporary integer now void fun1(const int & num); this function can receive from myfun().BUT void fun2(int & num); this function cannot receive from myfun() Why is that, Moreover what is lifetime of a temporary object like one returned in myfun() ???
