I'm trying to make an templated class of List and trying to make a list of Students(another class) which I made. Its not working.
Code seems to work fine for pre-defined data types but it crashes when it comes to students. I also want to run sort function on list of students.
I would like to define a templated class while implementing default value on templated arguments. I don't know how to do that with string templated variables.
For exemple:
Code:
template <class T>
class A {
public:
A() { version = ???? }
std::string_base<T> version;
};
I don't want to pass the default value as parameter of the constructor. how I can do this?
I am making a simple program that is suppose to make a list of champions and their items from the game League of Legends. I am stuck on making a vector of the class so each slot within the vector would hold each champion and its data. This is what I got:
Champion_Info.h
#ifndef CHAMPION_INFO_H_INCLUDED
#define CHAMPION_INFO_H_INCLUDED
#include <vector>
#include <string>
using namespace std;
class Champ_Info
[Code] ....
I have a .cpp file which contains 5 smaller defined classes. In my missile class I have a default constructor and a constructor that I invoke
class Missile{
private:
bool isHuman;
[Code]...
My issue is when creating and adding the pointer object; it doesn't seem to create a new instance of the class-the Missile objects all share the same xPos value which is always the first xPos when the "fire" command is given. The "Missile *missile = new Missile(xPos, yPos, true);" line does not seem to create a new instance of the object with different variables but instead creates a new object with the same variables. Is it necessary for me to always make a separate .cpp and .h file for any class I want to create multiple instances of or can I keep the smaller classes in the same file and still create a new separate instance of the class?
I'm making a minimal spanning tree class that inherits a graph class, both are templated. This is my mstree.h so far:
#ifndef _MSTREE_H_
#define _MSTREE_H_
#include "graph.h"
namespace MSTreeNameSpace
[Code]...
and I keep getting these errors:
mst.h:9:25: error: expected template-name before ‘<’ token
class MST : public Graph<T>
^
mst.h:9:25: error: expected ‘{’ before ‘<’ token
mst.h:9:25: error: expected unqualified-id before ‘<’ token
I'm trying to template the return type for this function (component), I've looked around for example code but there doesn't seem to be any exactly like what I want.
Entity.hpp
class Entity {
public:
Entity();
unsigned int id = 0;
Component& addComponent(std::string);
[Code] ....
Error : 'ent1.component<HealthComponent>' does not have class type
I need to create a templated doubly linked list, with an iterator class within the list class. This program is to function just like the STL list class but I only need to implement functions that I am using, My trouble is I am kind of clueless on the iterator part and the fact that the list is templated is giving me syntax grief. I have pasted the code I have done so far.
1. On the syntax implementing the list and iterator functions outside of the class
2. I am not sure when to deference the iterator in the functions, but think I have it right so far
3. For the reverse function can I copy the list into a new list in reverse then re add them to the original list overwriting the same values? I have the code I have so far there
4. For the iterator erase function, I am not sure if I am deleting the node correctly.
5. I am not sure if I need template <typename T> above the iterator functions. Does the iterator class need to be a template? Right now it is not.
// Templated doubly linked list class
#include <iostream>
using namespace std;
template <typename T>
class list {
private:
Node *head;
Node *tail;
[Code] ....
I've this variadic template class implementation:
// Predefine template delegate factory
template < typename R, typename... Args >
class brGenericDelegate ;
// C++11 template alias to announce functor definition
template < typename R, typename... Args >
using brGenericDelegateType = std::function< std::shared_ptr<R>(Args...) > ;
[code]....
This template works fine for me. Now I have to compare, if the functors of the generic templates are equals ore not. Actually I see no way to reach this aim, because I've to cast the brDelegate on each request.
Can I determine if a templated class has a particular constructor, in my case using a string within function to which T is used?
Code:
template<class T>
void MakeObject(std::vector<T>& dataVector)
{
std::string str "con string,Joe,24";
// catch if T has string constructor
T someObject(str); // T someObject should have constructor from string
dataVector.push_back(someObject);
}
I want to specialize a particular function for Integer datatype inside a class template. My XX.h will be
namespace ZZ {
template <class T>
class XX {
void doSomething(T x);
};
}
provide me XX.cpp which has template specialization for the function doSomething on Integer datatype.
I tried the following in XX.cpp
#include "XX.h"
using namespace ZZ;
template <class T>
void XX<T>::doSomething(T x) {
[Code] ...
But this code is not working.
I have a 2D array, array[20][3]. Each row represents a storm and each column represents month #, wind speed, and pressure in that order. This data is read from a file and auto-fills the array. I need to be able to give users the ability to add an additional storm or delete a storm. I know that a linked list would be the best approach but I'm not very familiar with linked lists.
View 1 Replies View RelatedI want to make something like this for a game:
It is a "list box" that has 2 scroll buttons (scroll bar not needed). One button push, "scrolls" the list one entry.
Needs to run crossplatform (windows, linux).
I want to make something like this for a game:
Attachment 30507
It is a "list box" that has 2 scroll buttons (scroll bar not needed). One button push, "scrolls" the list one entry.
Needs to run crossplatform (windows, linux).
I am having some serious issues with class inheritance. I am trying to make a MoneyBag class inherit from a class called bag. This will not work. I get an error complaining: error: expected class-name before '{' token. And yes I have googleing it and tried several of the various solutions offered with no avail.
The MoneyBag is pretty simple right now as I wanted to get it connected to bag before I tried to do anything with it.
//MoneyBag.h//
#ifndef MONEYBAG_H
#define MONEYBAG_H
#include <bag.h>
class MoneyBag : public bag{ ////<<------ Error appears on this line.
[Code] ....
So based on everything I have seen on line the statement:
class MoneyBag : public bag{ is legal.
As it is done this way on this very site's tutorial:
class Rectangle: public Shape, public PaintCost{
I'm trying to make a class constructor within a namespace and I keep getting errors like: "'<variable>' is a nonstatic data member of class '<class>'" for when I try to setup parameters, and "Incomplete type is not allow" whenever I try to write out my function definition. Here's what I'm doing:
namespace test {
class blah;
} class blah {
typedef int var[5];
[Code] .....
Also I'm unsure why there is a parameter of 'const blah &' when I mouse over blah(); (using Visual Studio 2010) within the class definition. It tells me 'blah::blah(const blah &)' and I am unsure where the parameter comes from. How can I resolve these issues?
I'm trying to make a very simple game in SFML, and i have a problem. Whenever i try to create sf::Sprite for the class where all properties of Player (his sprite, health, speed, etc.) It gives me error.
#include <sfml.h>
#include <list>
class Playerclass{
public:
int xspeed, yspeed;
float health;
sf::Sprite entsprite();
[Code] ....
The error is with player.entsprite.setTexture(texture) : "'player.Playerclass::entsprite' does not have class type".
template <typename T> struct avl_tree {
T data;
int balance;
struct avl_tree <T> *Link[2];
static int (*comp)(T, T);
};
In main, I have a function like so:
int compare(int a, int b) {
return ( a - b );
}
Now how do I assign the function pointer in my avl_tree class to the compare function?
I did this:
int (avl_tree<int>::*comp)(int, int) = compare;
But I got the compiler error:
Tree_Test.cc: In function ‘int main()’:
Tree_Test.cc:27:42: error: cannot convert ‘int (*)(int, int)’ to
‘int (avl_tree<int>::*)(int, int)’ in initialization
I'm trying to generalize the following (working) code:
#include <iostream>
#include <string>
#include <cmath>
int foo (int num) {return num;}
int foo (double num) {return std::round (num);}
int foo (std::string str) {return str.length();}
[code]....
Template argument deduction failed, it says. And using pred_action<T> and pred_action<FIRST> only makes it worse.Do we need to use a visitor pattern or something like that?
This problem just seems really strange to me because it is simple yet for some reason my class cannot pass into another class. The class PASS_OBJECT has a static array (even with 1 element this doesn't work) and when I try to pass this class (after it is initialized) I seem to lose the data inside the PASS_OBJECT. Not only that but even when I declared the class OBJECT with the type of PASS_OBJECT<int> I seem to lose the integer 99. Here's the code, note that if you comment out line 89, 92 and 93 you will notice that line 90 outputs In main 2: 99 just fine but it doesn't otherwise???
#include <iostream>
const int size = 1;
template <class T>
class PASS_OBJECT;
template <class S>
class OBJECT {
[Code] ....
To generate output data, I'm printing a bunch of vector contents to files. Because the type of variable can differ between vectors, I wrote a templated printing function to print out whatever the content of the vector is. It looks like this:
template <class T>
void SomeClass::PrintVector(std::vector<T>& Values, std::string& outFile) {
std::ofstream out(outFile, std::ios::app);
[Code] ....
I added the fixed because some larger values were being printed in scientific notation. Everything works well. My test code includes 3 vectors of doubles and 3 vectors of unsigneds. All the unsigneds work well and two of the doubles work well, but the third doubles vector prints nonsense unless I disable the fixed.
The calling code is the exact same. I know the values in the vector are correct, because a) if I comment out the "fixed" flag it works, and b) one of the unsigned vectors is sorted based on the values in that double vector (after it is printed, so the sort cannot corrupt the vector print) and works perfectly.
The "nonsense" looks like chinese/weird characters, if that matters.
I declared a member method to a class in its header file and implemented it in the cpp file. When I build and run the project in XCode, everything works fine. When I try to do it with a makefile, I get undefined symbols linker errors.
parser.h
Code:
#ifndef ENGINE_SCRIPT_PARSER_H
#define ENGINE_SCRIPT_PARSER_H
#include <string>
#include "variable.h"
namespace ninja_game_engine {
[Code] ....
The exact makefile looks like this:
Code:
test:
g++
Code/Engine/Modules/Timer/timer.cpp
Code/Engine/Modules/list.cpp
[Code] ....
I'm pretty sure that there is a weird namespace gotcha that I'm unaware of that LLVM (default OSX compiler) is compensating for that g++ isn't. Or maybe something weird with the optimization? I want the tests running at that level to make sure everything that is volatile is declared as such.
Rest of the code located here: [URL] ....
On several occasions in my project, I need to sort elements (indeces) based on their linked values. Those values are stored in an array. This means the comparison looks like this:
bool operator()(int i, int j) { return someArray[i] > someArray[j]; }
Because this form returns often but someArray may differ, I wrapped this in a template class:
template<class T>
struct sorter {
std::vector<T>& data;
sorter(std::vector<T>& __d) : data(__d) {}
bool operator()(int i, int j) const { return data[i] > data[j]; }
};
Now, I want to use this in a different way: I want to select the K indeces with the lowest value from someArray attached to it. My idea was to build a priority_queue, push the first K elements and then compare all the next elements to PQ.top(), as such:
INDEX t(0);
for (; t < someLimit; ++t) {
pq.push(t);
if (pq.size() == K) break;
}
for (; t < someLimit; ++t) {
if (someArray[t] < someArray[pq.top()]) { pq.pop(); pq.push(t); }
}
My problem, however, is the definition / initialization of the priority_queue object. My first idea was simply std::priority_queue<INDEX> pq(sorter<VALUE>(someArray));, but calling any function on pq provides the error "expression must have class type" (?) when hovering over pq.
My second guess, std::priority_queue<INDEX, std::vector<INDEX>, sorter<VALUE>(someArray)> pq;, provides the error 'expected a ')'' when hovering over someArray.
What is the correct way to initialize this data structure?
I've been studying the heck out of the boost metafunction libraries. I understand a good deal of what things like varadic functions and integral sequence wrappers are, but I am having a hard time putting everything together to get working functions, such as performing arithmetic operations or functions like that of std::vector.
Here is an example of what I'm talking about:
// Sequences
template<typename T... N> struct seq;
template<typename T, T... N> struct seq_c;
// Integral constant wrapper
template<int T> struct int_
[Code] .....
My knowledge of all of this is pretty scattered and I've really been trying hard to put it all together. Is this correct? How can I apply this and use it to do more?
I am working on building a set of templated data structures for my own learning and have run in to an error when instantiating my templated linked list. I receive the following error:
error LNK2019: unresolved external symbol "public: __thiscall LinkedList<int>::~LinkedList<int>(void)" (??1?$LinkedList@H@@QAE@XZ) referenced in function _main
--LinkedList.h--
#ifndef LINKEDLIST_H
#define LINKEDLIST_H
template<class T>
class LinkedList {
[code]....
why I would be receiving this error?
How can I get the items from a list into textboxes. I am doing an windows form application in visual studio.
I have the first form with a couple of textboxes.
I want the inputs be saved in a list. And then displayed in another form. How to move on. The class with the list looks like this:
public class Casecs {
public List<caseInformation> fallInformation = new List<caseInformation>();
public class caseInformation {
public string caseId { get; set; }
public string phoneNumber { get; set; }
public string description { get; set; }
}
Then the form with the inputs in textboxes looks like this:
Casecs Casecs = new Casecs();
Casecs.fallInformation.Add(new ERIS.Casecs.caseInformation {
caseId = txtCaseId.Text,
phoneNumber = txtPhonenumber.Text,
message = txtMessage.Text
});
Then where I am stuck a form with some textboxes where I want the list items to be displayed:
public partial class btnDispatch : Form {
public btnDispatch() { }
public btnDispatch(List<Casecs.caseInformation> fallInformation) {
InitializeComponent();
I'm trying to develop a program that stores a list of hw assignments in the form of "Date,Assignment name,grade". I have functions that add,remove, and delete from a list, but I would also like to search and delete a particular date found in the list. From here, split - Splitting a string in C++ - Stack Overflow I've tested Evan Teran's method to split a string, but I'm unsure of how to implement it in my code.
List.h Code: #ifndef LIST_H
#define LIST_H
#include <string>
using namespace std;
class List{
[Code] .....