When we want to use custom classes for the STL set data structure, how to do it?
I look around and see people passing comparators, overloading operator(), and also overloading operator< in the class itself.
Which one's the idiomatic c++ way?
Let's say we have a custom Vector class and I need to know which of the following is considered to be more efficient and why of course.
Vector Vector::operator+(const Vector &b) const {
return Vector(x+b.x,y+b.y);
}
Vector Vector::operator+(const Vector &b) const {
Vector tmp(x+b.x,y+b.y);
return tmp;
}
I am currently working on a custom "Array" class for a project, and I have run into an error I don't quite understand the source of. The relevant code is as follows:
template<typename T> class Array {
private:
T errValCopy;
public:
T __errVal__;
uint16 __size__;
T* __ptr__;
Array(const T& errorValue);
[Code] ....
When I try to run the following code:
Array<Array<int>> a(Array<int>(-1));
The error log tells me there is no appropriate default constructor available. If I understand it correctly, "default constructor" refers to the constructor which lets you just write Array<int> a; instead of Array<int> a(...);, but I can't see where in the code such a situation occurs...
I have made a custom class matrices class which allows me to add, multiply, subtract (etc.) matrices. I have the following method for multiplication but I get an error that says
'invalid use of 'this' outside of a non-static member function'
How can I refer to the current instance without getting this error.
void operator *(Matrices& matrix2) {
this.multiplyMatrix(matrix2);
}
I attempted to create a dynamic array class for use in my engine (due to problems regarding a dll-interface with the standard library), so I tried at making a standard-compatible allocator template class first. After I "finished" that, I went on to work on the dynamic array class itself.So I finish the dynamic array class, and test it with the standard allocator. It works perfectly, but when I test it with my custom allocator class, it fails terribly.
To make sure it wasn't my DynamicArray class that was causing issues, I tried using the custom allocator on the std::vector class template, and it didn't work either. IMy DynamicArray class code:
// Represents a dynamic array, similar to the standard library's "vector" class.
template<typename T, typename A>
class DynamicArray
{
public:
DynamicArray() :
data(nullptr),
elements(0),
capacity(0)
[code].....
The "Request" and "Free" functions are my engine's equivalent of malloc and free (or new and delete). I allocate a large buffer (16 mb), and through those functions I distribute the memory to where it's needed.
Right now I have code
#include <iostream>
using namespace std;
class Rectangle {
private:
double width;
double length;
[Code] .....
it gives error ...
I have a class like this:
#include <string>
using namespace std;
//-----------------------------------------------
class Prenumeratorius {
private:
string pavarde;
string adresas;
string leidinioKodas;
[code]....
bunch of variables, constructor, setter and getter.And I have this class:
#include <vector>
class Leidinys {
private:
string kodas;
string pavadinimas;
double vienetoKaina;
[code]....
in to my "Leidinys.h" header file, I get a build error, I tried to remove same includes in both files, that didn't worked.
I have a variable named Authors. Sometimes I will insert one author into the database, sometimes more than one author will be inserted into the database.
The page that performs the update is a .cs page. Here is the layout:
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
[Code]....
This definitely works for updating one author's name:
if (old.Author != Author) RequestItem.UpdateField(LibraryDocID, Editor, "Author", Author);
I just can not nail down how to insert a string of author's names.
If I have an array of some class, and that class has const members, is there some way I can call a custom constructor on elements of the array?
I can't seem to reinitialize an element in foos in the example below. A thread on stack overflow mentioned the copy constructor show allow it, but I get "no match for call to '(Foo) (Foo&)'" when I try it.
Code:
class Foo {
public:
Foo();
Foo(int x, int y);
[Code] .....
how to solve this undeclared error when compiling this code. I assume it has something to do with scope.
C code - 47 lines - codepad
Code:
#include <stdio.h>
int main(void) {
struct bank_account {
[Code].....
I am trying to create an structure of data with following elements:
struct stest {
std::vector<int> na;
std::vector<double> nb;
std::vector<double> va;
std::vector<double> vb;
std::vector<double> vc;
std::vector<double> vd;
}
I would like to modify the composition of this struct, so that I can create a special data structure by
vector<stest*> data_test;
for(int i = 0; i < 10; i++)
data_test.push_Back(new stest);
within this structure, I have: only one na and one nb, but ten groups of combination of va, vb, vc, vd that I can access by pointer, which means na, nb are independent but still inside of the structure.
I'm currently having the following data structure:
typedef struct {
int a;
int b;
} S;
<vector <vector<S> > v;
Now I also have different pointers that can be set in connection with one instance of the above shown vector. Therefore I was attempting to work with a map:
map<p*, <vector<vector <S> >, vector<sI> > m;
However, it seems like it doesn't work that way. Therefore I tried the following:
map<p*, map<<vector<vector <S> >, vector<S> > > m2;
With this attempt I do now, however, get another mistake here, that [] cannot be used here:
S s;
m2[p][0].push_back(s);
Does it use Linked List or Dynamic Array?
I want to know this because if I happen to want to use a lot of insertions and deletions then it is more efficient to make use of Linked List instead of Dynamic Array.
While, if I happen to want to just access random parts of the Array, then Dynamic would be more efficient.
I want to make a 2D game using SDL engine and I need to check whether or not an object is colliding with a list of other objects. (because there would be more then one objects on the map.)
Since I would simply be accessing each object sequentially to check whether or not the object is colliding with another the object in question, and since any of those objects could "die" and be deleted at any time, it makes more sense to use Linked List then a Dynamic Array.
I created one structure and the created structure is using in few more structures, but i did not get the proper data.
typedef struct _MSG_HEADER{
//MESSAGE_HEADER 40 bytes
short iApiTcode;
short iApiFuncId;
int LogTime;
char AlphaChar[2];
[Code]...
My requirement is have to fill the MessageHeader structure & we can use that header in all the structures entire program.
I have two structs like below,
struct SP {
string sp1;
string sp2;
};
struct SL {
[Code] ....
How to add data to slVect ?
I have this data store into a data structure.
i j x y w h w*h
0 0 0 0 9 11 99
1 0 0 11 9 10 90
2 0 0 21 9 11 99
0 1 9 0 8 12 96
1 1 9 12 8 7 56
2 1 9 19 8 6 48
[Code]...
Code:
struct data {
//Here
/*! horizontal position */
int x;
/*! vertical position */
int y;
/*! width */
int w;
/
[Code]...
data and then i have an array /*! it contain group_id of each data line*/ int group_id[16]={0,0,0,0,3,3,1,1,1,3,3,2,2,2,2,1}; I never worked with 2D array before. My problem is that i want to create a 2D array of that data for example if i write data[j][i].. It will give me the reference/value of all data lines that belongs to j column, and same with group_id[j][i]. I don't know how i can store these structure vaules in this like 2D array.
Corporate Data Sales
Write a program that uses a structure named CorpData to store the following information on a company division.
Division Name(North, South, East, Or West)
First quarter sales
Second quarter sales
Third quarter sales
Fourth quarter sales
Total annual sales
Average quarter sales
Include a constructor that allows the division name and four quarterly sales amounts to be specified at the time a CorpData variable is created.
The program should create four variables of this structure, each representing one of the following corporate divisions: North, South, East and West. Each variable should be passed in turn to a function that calculates and stores the total annual sales and average sales for that division.
Once this has been done for each division, each variable should be passed in turn to a function that displays the division name, total sales, and average sales.
Here is my code:
#include "stdafx.h"
#include <iostream>
#include <string>
using namespace std;
struct CorpData {
[Code] ....
To check if a set B is a subset of A or not. Which data structure to be used to store set A for quicker response(linked list/hash map)? What if I want to check intersection also?
View 1 Replies View RelatedSo I've been working on implementing a stack data structure as an ADT, the program compiles, but when I try and push elements on top of the stack, for some reason the stack is full.
#ifndef H_stackADT
#define H_stackADT
template <class Type>
class stackADT {
public:
virtual void initializeStack() = 0;
virtual bool isEmptyStack() const = 0;
[Code]...
Given a set of different types of paired symbols; determine whether it is balanced or not (the opening and closing version of each type are paired correctly). Any other type of characters may appear in the input will be neglected.
For example:
(**(*[*])****) is balanced, also [{}**[]**()]** is balanced. But ((*{*)*}) is unbalanced as well as [()***[]***{*(*)}.
Write a C++ program that requires a string containing and expression as an input from the user and check for balanced bracket pairs using stack data structure.
Here is my code which give me nothing when I run it.
#include <iostream>
#include <string>
using namespace std;
class CustomStack {
[Code] ....
I want to know if you have made Sudoku game in c++, which kind of data structure did you use? shortly, which part of the game did you use for? [Array, Stack, Queue, Linked List, Binary Search Tree]
View 5 Replies View RelatedI need building a complete graph from a file. The format in the file is as follows.
[ vertex 1] [ x_coordinate 1] [ y_coordinate 1] [cityname 1]
[ vertex 2] [ x_coordinate 2] [ y_coordinate 2] [cityname 2]
. . .
[ vertex n] [ x_coordinate n] [ y_coordinate n] [cityname n]
What kind of data structure shall I use in order to store date in a complete graph so there is an edge between every pair?
Data handling for a UAV project I am trying. My background is in Microcontrollers but I have never had exposure to "sound" programming practice...
I have got 2 microcontrollers to drive a UAV craft I've made. One "firmware" micro collects all the sensor data and then passes it to the other "application" micro for control processing. Once decisions have been made this is sent back to the "firmware" micro so that actions are taken.
So in essence I am sharing a raw data chunk periodically between the 2 processors that has outputs and feedback data. For the moment this is captured as one big buffer array on either micro after receiving. For easier structure I thought of bouncing this buffer that contains all sensor information and control variables between the 2 processors (visualize a ping pong game with all the possible variables from both micros - bandwidth between the micros is not a limitation) There are quite a few modules that want to access information from this buffer and write control actions back to it.
I was thinking of constructing a struct on both micros to access this "raw data" from the buffer and set it up with variable names so that it is easier for functions to read info and write controls back.
But this would mean that the data is accessible to every function, and there is the fear that some functions will write to the input data or write to control variables that they should not have access to. I also need to reduce memory copies and the like due to limited memory on each micro.
Been given an assignment to create a predictive text program. What data structure I should use for this and the steps I should take when I make the program?
View 12 Replies View RelatedData structure problem. I have a table of the following format:
Code:
C/R 1 2 3 4 5 6 7 ...
1 x x x
2 x
3 x
4 x
5 x x x
6
... s
So my column and row names are integer numbers if an outcome of some game for a certain column and row lable is a match then we have an x on that position. The size of the integer names for both column and row name is quite large (let us imagine that it is so large that you would need a machine with 500GB of RAM memory to hold this type of table even if x's are treated as regular char's) . In every row there is at least one x and for every column the same holds for the columns. However, the number of x's for a row or a column can be bigger then 1. How to store this table efficiently? (using as less memory as possible).
The data structure should be efficiently accessed in the column fashion that is, if i want to get all values for column 4 I should be able to do that in O(N) time where N= the number of rows.
// This program creates a structure to hold data for a kennel
#include<iostream.h>
struct KennelList {
int dogID;
char gender;
int age;
[Code] ....