unsorted_set hashing error [closed] - c++

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I recently started to make a game with a friend, but we now encountered a problem with unsorted lists. I checked this site and other forums, but nothing seems to work.
Here's the code: http://pastebin.com/nx8sf6T2
And the compiler error: http://pastebin.com/fdQ7B0Dx
(And for compiling I use "clang++ -std=c++11 main3D.cpp", in case anyone is wondering)

hash<point> must be known at the time of instantiation of std::unordered_set<point>, and that requires point to be known before hash<point>:
struct point
{
// contents...
};
namespace std
{
template<>
struct hash<point>
{
// contents...
};
}
struct line
{
std::unordered_set<point> points;
// contents...
};
namespace std
{
template<>
struct hash<line>
{
// contents...
};
}
Demo

Related

Unable to access helper functions not in the namespace: undeclared identifier [closed]

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I currently have a namespace set up like this:
SomeClass.h
namespace somenamespace {
class SomeClass {
public:
foo();
}
}
SomeClass.cpp
namespace somenamespace {
SomeClass::foo() {
somehelperfunction();
}
}
void somehelperfunction() {
std::cout << "hejflsdjf\n";
}
Without changing my header file, I cannot find a way to implement this helper function in a way which allows my class implementation to access the helper function. I was under the impression that as long as the helper function was in the same file I would be able to access it within the class implementation. But I get a "undeclared identifier" error when trying to build.
Functions must be declared before called.

Problem with static data member - fixing linking error creates a compiler error [closed]

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Closed 2 years ago.
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game.h:
enum Game_state { MAIN_MENU, /*...*/ };
namespace list { class Linked_list { public: Linked_list() {} }; }
class Game {
public:
static Game_state state;
static list::Linked_list<Obj> objs;
};
Game_state Game::state = MAIN_MENU;
list::Linked_list<Obj> Game::objs = list::Linked_list<Obj>();
This gives me the linker error: multiple definition of Game::state (and Game::objs).
If I take out the type specifiers it gives me the compiler error: 'state' in 'class game' does not name a type (same for objs).
All I need is to initialize these members.
I'm using mingw on 32 bit windows 10.
You have to move those definitions into a translation unit (cpp file). Otherwise you will redefine them every time you include the header file somewhere, violating ODR.
Put the definitions of 'game::stat' and 'game::objs' in a *.cpp file and link against it.

will be initialized after [-Wreorder] [closed]

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Closed 3 years ago.
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When I compile my files I get this warning :
In file included from AsyncSQL.cpp:8:0:
AsyncSQL.h: In constructor 'CAsyncSQL::CAsyncSQL()':
AsyncSQL.h:192:10: warning: 'CAsyncSQL::m_iCopiedQuery' will be initialized after [-Wreorder]
int m_iCopiedQuery;
^
Here is my AsyngSQL.H http://pastebin.com/u72kyuq7
So what am I doing wrong?
The problem is the order in which you initialize members in the initializer list on line 22,
_SQLResult(): pSQLResult(NULL), uiNumRows(0),
uiAffectedRows(0), uiInsertID(0)
These should appear in the same order as they appear in the class definition. For example:
class test {
test(): foo(1), bar(2) { }
int foo;
long bar;
};

calling static function from constructor of same class [closed]

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Closed 9 years ago.
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can we call static function from constructor of same class.
class a{
static void fun();
a() {fun();}
};
it is giving an error while linking code. I am using visual studio C++, 2010.
Yes you can - as long as you provide a function definition for the static function as well.
I don't really understand the question.
If you provide a function definition as said by Billz and Ogni42, it will work.
The following code does compile, and work:
#include <iostream>
class a {
public:
a() { fun(); }
private:
static void fun();
};
void a::fun() {
std::cout << "BOAP" << std::endl;
}
int main() {
a foo;
return 0;
}

Problem using recursive method in c++ [closed]

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Closed 5 years ago.
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I have a class, defined in a .h like this
#ifndef JLLABOUR_H
#define JLLABOUR_H
class JLLabour{
public:
JLLabour(int, int);
double* recursivefft(double*,int);
void FFT(int*);
~JLLabour();
private:
int width;
int height;
};
#endif // JLLABOUR_H
and in my .cpp I have the definition of my recursive function, the problem is that when I call it again , during compilation it doesnt allow me to continue because the method has not been defined yet. I dont know how to solve this, please help.
#include <JLLabour.h>
double* JLLabour::recursivefft(double* x,int asize){
//operations and declartions...
//...
even = recursiveFFT(sum,m); //<-- the problem is here, in the recursion.
odd = recursiveFFT(diff,m);
// more operations....
return result;
}
}
FYI I am compiling under Linux, using Qt because Im developing a graphic app...
C++ is case sensitive. Your method is called recursivefft not recursiveFFT.