C++ :: Singleton Class - Auto Seems To Return Wrong Type
Jul 18, 2013
I am trying out a technique for a singleton class:
// access controlled singleton, accessed through function "instance()"
// singleton is constructed in this function
// so that constructor and destructor will be used
class single {
// private constructor/destructor
[Code] .....
Playing around with the code in main(), I am having trouble with auto:
single& s = single::instance(); // works fine
auto a = single::instance(); // error ~single() is private
When I make the destructor public, the output of the program is:
ctor
dtor
dtor
So I fixed this by typing auto&. I'm still confused though, why wouldn't auto know I am returning a reference?
View 2 Replies
ADVERTISEMENT
Feb 25, 2014
i'm getting a new error is a wrong return type.
WebAPI.cs
namespace DarkAPP___WForm.Libs {
class WebAPI {
System.Net.WebClient wc = new System.Net.WebClient();
public WebAPI() {
[code].....
View 6 Replies
View Related
Nov 24, 2013
I am trying to create a flexible interface for my CL application. And what i have is this :
Code:
using namespace std;
// iplcp -i queryFile -d databaseFile
template <typename INT, typename CHARA>
class API {
vector<string> files;
vector<INT> flags;
[Code] ....
and in main :
int main(int argc, char **argv){
//set variables
API<int, char**>args(argc,argv);
cout << "In file: "<< args.GetOpt("i") << " Db file: " << args.GetOpt("h") << endl;
}
// first thing to be printed should be string and the second int
I know this is not probably the best way to but i am laying around and was curious if something like this could work . Are there any good C++ templates for CLI applications from which i could learn?
View 7 Replies
View Related
Apr 25, 2014
I am writing a class Player which has several char arrays as private fields. I am trying to write a method which returns an array as a pointer, but doesn't alter the array in any way, thus the const.
Here is a snippet:
Code: class Player
{
private:
char state[MAX_STATE_CHAR + ONE_VALUE];
int rating;
char last[MAX_NAME_CHAR + ONE_VALUE];
char first[MAX_NAME_CHAR + ONE_VALUE];
int groupNumber = NEG_ONE;
public:
char * GetFirst() const
{
return first;
}
Visual studio is saying that the return type doesn't match.
View 3 Replies
View Related
Apr 25, 2014
Code:
returnType operatorOperatorSymbol (parameterList); // syntax for operator overloading
Class Fraction
public:
Fraction operator-(const Fraction& f1){
Fraction r;
return r;
}
Is this even syntactically correct? It gives me errors. Im just trying to compile it without errors. I think the function makes sense since its returning a type Class
View 2 Replies
View Related
Jan 17, 2013
I have the following code where I use the singleton design pattern, but I get the warning:
warning C4715: 'CM::Instance' : not all control paths return a value
Code:
CM& CM::Instance() {
DWORD dwWaitResult = WaitForSingleObject(mutex, INFINITE);
switch(dwWaitResult) {
case WAIT_OBJECT_0:
[Code] ....
How can I fix this warning?
View 4 Replies
View Related
Apr 17, 2014
Here is my code to find the index of a string array whose string is equal to the query string. I have checked the program can return the correct index, but the cout result is totally wrong.
#include <iostream>
#include <string>
using namespace std;
[Code].....
View 4 Replies
View Related
Oct 6, 2013
I've tried to program a Singleton class. But the problem is that I don't know how to access the g_pInstance() function. Because this is not working because the constructor and deconstructor is private:
Singleton::g_pInstance()
Code: #include <iostream>
using namespace std;
class Singleton
{
[Code]....
I'm not sure of how to access any object, function, variables in the class when you are using a Singleton. How do you access that?
I'm just asking because I want to know how to do that if I have to use a Singleton sometime when I'm programming.
View 5 Replies
View Related
Oct 11, 2014
My current idea of how to work with user settings goes like this:
1. Create a class to hold all of the user settings.
2. Use that class to load/save/hold settings in memory.
3. Create an instance of that class once in the entry point of the program (int Main or whatever).
4. Pass, by reference this same class instance around to all of the other classes that need the user settings.
5. Once all other objects deleted, save and then delete the User Settings class.
I created a psuedo-code example below of this. My question is if this is the best way or should I be doing something else. In particular, I am wondering if somehow I can avoid passing the settings class by reference all of the time. Would this be a good case scenario for a "Singleton" type class?
#include <string>
class UserSettings {
private:
std::string SettingOne;
int SettingTwo;
bool SettingThree:
[Code] ....
View 9 Replies
View Related
Jul 13, 2014
#include <map>
#include <iostream>
#include <stdexcept>
[Code]....
SuperSmartPointer<int> ptr4((int*)ch); this line gives error error as double deletion will occur.
Solution :
1) make the reference map global variable.
2) wrap the map in a non-template singleton class.
View 1 Replies
View Related
Aug 20, 2014
I'm playing with the idea of a singleton base class, but I'm having an issue with how to implement the GetInstance() function in the base class. Since I'm trying to make this ridiculously simple for the child, I'd like to handle that in the base.
class Singleton {
private:
static Singleton* instance;
Singleton() { Construct(); } // Private to avoid other instances
[Code] .....
It would be easy to use like so:
class Hello : public Singleton {
private:
std::string hello;
void Construct() { hello = "hello"; }
public:
std::string GetHello() const { return hello; }
};
Then the instance would be handled like so:
std::cout << Hello::GetInstance()->GetHello();
View 12 Replies
View Related
Feb 16, 2012
This code is for (hospital management system).
This code allow you to add patients.
There are two types of patients. which is:
1. Normal patient.
2. Critically ill patient.
once you added any patient. You will be able to show all patient using "ShowAllPatient;" method. -> i want the Auto-increment ID Number to appear for each patient has been added.
And you will be able to call a patient to provide a hospital services for him/her using "GetNextPatient;" method.
I need to generate an Auto-increment Number for each (patient) has been added. (Auto-increment Number) but it just should be different for each patient. For example the first patient will have 1, The second patient will have 2. etc. The Auto-increment number should appear for each patient.
View 14 Replies
View Related
Jan 24, 2014
Writing a smart array class for my C++ class. I'm running into a problem where the constructor apparently throws the wrong exception. Compiled on G++ with C++11 extensions enabled.
Code:
// headers
#include <iostream>
#include <utility>
#include <cctype>
// stuff we need from namespace std
using std::cout;
using std::cin;
[Code] .....
When I try to check the error-handling code, when I enter a size less then two, Array's ctor throws InvalidSize, and gets caught, all good. But when I enter a letter, the ctor also seems to throw InvalidSize!
View 14 Replies
View Related
Feb 26, 2015
understand the below program.
Why I'm getting output y is 6.000000
Code:
#include <stdio.h>
int square(double a);
int main()
[Code].....
View 6 Replies
View Related
Nov 21, 2012
Say I have overloaded functions with different arguments AND return types. Each set of argument has only one corresponding return type.
Code:
Vector grad(Scalar)
Tensor grad(Vector)
Later I have:
Code:
template <class T>
void test(T x) {
... Y = grad(x)
}
Then how do I automatically declare the type of Y. Do I need to make the grad function a template and specialize each of them ?
View 4 Replies
View Related
Apr 29, 2014
I am new to c++ and trying to learn. for instance. i have a struct and method.I am trying to learn what i can do with the method if i define the return type as struct type.
struct S {
int age;
string name;
};
S method() {
//what i can do in here. with the Struct. I mean can i reach members of the struct. etc
}
View 2 Replies
View Related
Apr 7, 2014
I am wondering why return type for an assignment operator cant be a void or int? Cant I write assignment operator for student class like this as we do nothing with returned value?
Student {
char name[20];
int marks;
public:
student(char*name,int marks)
[code].....
View 2 Replies
View Related
Apr 7, 2014
In my main I have a do/while loop, which is to iterate around the method calculateImportance while i is not equal to the numNodes.
do
{
int i;
int numNodes = Test.count();
for(i=0; i<=numNodes; i++)
[Code]....
I have been messing around with the data type node, hence why it is there are present, but, that doesn't seem to the answer
This is the function declaration in the header file.
node CalculateImportance();
View 1 Replies
View Related
Jan 17, 2013
i heard that it was int but later it is deprecated , so at present what is the default return type of a function ?
View 4 Replies
View Related
Jul 13, 2014
/*
* symboltable.c
*/
#include "symboltable.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "include/utlist.h"
[Code] ....
View 2 Replies
View Related
May 28, 2012
I want my function to return the type mpz_t, but I'm not sure how?
I've tried: mpz_t MyFunction(mpz_t A, mpz_t B){}
But it didn't work, here is my code so far, I have bolded the parts of the code which are causing errors and added the errors in the comments:
Code:
#include <iostream>
#include <mpir.h>
using namespace std;
???? A(mpz_t m, mpz_t n){
mpz_t mmo; //used to store the value of m, minus one
[Code] .....
Is there a way around this?
View 5 Replies
View Related
Apr 4, 2013
I am having problems with my function definition of a function that should return a structure value.
This is the error I get compute.cpp(9): error C2146: syntax error : missing ';' before identifier 's_advertisebus'
The error is on the line where I start my function definition typing my function type as a structure. A long time ago in c the keyword struct is used with the structure type like struct s_advertisebus s_readadbus(). I tried it both ways but I got errors.
// struct.h
#ifndef STRUCT_H
#define STRUCT_H
struct s_advertisebus {
int nnumberofads;
float fpercentused;
[Code] ....
View 2 Replies
View Related
Jan 29, 2015
I always have confusions while using pointers with functions both as arguments and as return type.
View 1 Replies
View Related
Oct 6, 2012
If we are using strcpy() for copying the string. As we are passing pointers to it It will copy the string & no need to return the string .This function will finely work with return type as void then why Ritchie has used it as char* strcpy()?
View 4 Replies
View Related
Jul 27, 2012
Is this really the preferred way to get the return type, for use in a derived class, of a function defined in the template parameter?
template<class PARAMETER> class C {
protected:
typedef typeof (reinterpret_cast<PARAMETER*>(0))->function() returntype;
};
This works just fine for me, but seems inelegant.
View 12 Replies
View Related
Dec 9, 2013
I have this code:
#include <iostream>
#include <vector>
#include <map>
#include <string>
using namespace std;
[Code]...
and it does not compile.
The error is:
test.cpp: In function ‘int main()’:
test.cpp:20:30: error: no matching function for call to ‘func1(std::vector<int>&)’
test.cpp:20:30: note: candidate is:
test.cpp:8:45: note: template<class T, class U> std::map<T, T> func1(U)
test.cpp:8:45: note: template argument deduction/substitution failed:
test.cpp:20:30: note: couldn't deduce template parameter ‘T’
View 3 Replies
View Related
