I have a header file, RandFunctions.hpp which contains a template function,
#ifndef _RANDFUNCTIONS_HPP_
#define _RANDFUNCTIONS_HPP_
#include <stdlib.h>
#include <time.h>
namespace surena
{
namespace common
{
template<typename RealT> inline
RealT
RealRandom()
{
return rand()/(RealT(RAND_MAX)+1);
}
};
};
#endif
and another header file, Search.hpp which includes RandFunctions.hpp,
#ifndef _SEARCH_HPP_
#define _SEARCH_HPP_
#include "RandFunctions.hpp"
#include <stdlib.h>
#include <time.h>
namespace surena
{
namespace search
{
template<typename RealT>
class CTest
{
public:
CTest() {srand((unsigned)(time(0)));}
RealT
GenRand(){ return common::RealRandom(); }
};
};
};
#endif
when I include Search.hpp in a cpp file, for example,
#include "Search.hpp"
int
main(int argc, char** argv)
{
CTest<float> test;
return(0);
}
I get the following compile time error:
‘RealRandom’ is not a member of ‘surena::common’
What is wrong here?
Since RealRandom is a template function with no parameters, you need to provide a template argument:
GenRand(){ return common::RealRandom<RealT>(); }
^^^^^^^
Also in your main you'd have to qualify your test variable with the proper namespaces:
surena::search::CTest<float> test;
^^^^^^^^^^^^^^^^
Related
Im using vscode and im new to c++. I learned how to create a header file link to its cpp and use it to main.cpp. The only problem bugs me out is why it causes an error this is my simple code.
Name.h
#include <iostream>
#include <string>
class myname
{
public:
void setname(std::string name);
void prname();
private:
std::string Name;
};
Name.cpp
#include "Name.h"
void myname::setname(std::string name)
{
Name = name;
}
void myname::prname()
{
std::cout<<"Hello :"<<Name<<std::endl;
}
Maiin.cpp
#include <iostream>
#include <string>
#include "Name.h"
using std::cout;
using std::string;
using std::endl;
int main()
{
myname Epoy; // IN FUNCTION INT MAIN: ERROR myname was not declared in this scope
Epoy.setname("Jomar"); //note myname <-rename "BUT THIS IS NOT THE ERROR CAUSE THIS JUST HAPPEN BECAUSE OF THE ERROR ABOVE "
Epoy.prname();
return 0;
}
also i tried so many method i even compiled this by using g++ Maiin.cpp Name.cpp - o Maiin
Still didnt work
Edit: Community want me to add more details.
What I asked was, have you write header guards in your header file: #ifndef Name_H, #define Name_H, #endif ? Since you use vscode you have to done it manually.
Like this:
#ifndef Name_H
#define Name_H
#include <iostream>
#include <string>
class myname
{
public:
void setname(std::string name);
void prname();
private:
std::string Name;
};
#endif
you missing a C++ constructor:
class Foo {
public:
Foo() { /* your init code */ } // <-- this is a std. C++ constructor
~Foo() { /* your clean-up code */ } // <-- this is a std. C++ de-structor
};
int main(int argc, char **argv) {
Foo bar; // here, you don't need the: ( ) object on heap !
}
Can you explain me why my function AllToAll is undefined in my example? I use CMake to generate a libNeuralNetwork.a which is called by the exemple.
LayerFactory.hpp
#pragma once
#include "LayerModel.hpp"
#include "Layer.hpp"
namespace nn
{
extern internal::LayerModel AllToAll(int numberOfNeurons, activationFunction activation = sigmoid);
}
LayerFactory.cpp
#include "LayerFactory.hpp"
#include "AllToAll.hpp"
using namespace nn;
using namespace internal;
LayerModel AllToAll(int numberOfNeurons, activationFunction activation)
{
LayerModel model
{
allToAll,
activation,
numberOfNeurons
};
return model;
}
NeuralNetwork.hpp
#pragma once
#include "layer/LayerModel.hpp"
#include "layer/LayerFactory.hpp"
namespace nn
{
class NeuralNetwork
{
public:
NeuralNetwork(int numberOfInputs, std::vector<internal::LayerModel> models);
//...
};
}
Example.cpp
#include "../src/neural_network/NeuralNetwork.hpp"
using namespace nn;
int example1()
{
NeuralNetwork neuralNetwork(3, {AllToAll(5), AllToAll(2)});
}
error message:
CMakeFiles/UnitTests.out.dir/ExamplesTest.cpp.o: In function `example1()':
ExamplesTest.cpp:(.text+0x8b3): undefined reference to `nn::AllToAll(int, nn::activationFunction)'
You have declared AllToAll in the top-level namespace and defined it in the nn namespace.
The following will not declare the function in the namespace:
using namespace foo;
extern void Bar();
You need:
namespace foo {
extern void Bar();
}
I'm being tasked with defining a struct within my main() function, but using it in other files. I have the code working if I define my struct inside my header file, but I cannot figure out how to define struct inside main() and still use it outside its given scope.
Example of what I have now:
3 files: main.cpp, header.h, and function.cpp
main.cpp
#include <iostream>
#include "header.h"
using namespace std;
int main()
{
vector<myStruct> myVec;
myFunction(myVec);
return 0;
}
header.h
#ifndef HEADER_H_INCLUDED
#define HEADER_H_INCLUDED
#include <vector>
using namespace std;
struct myStruct{
int typeInt;
string typeString;
double typeDouble;
};
void myFunction(vector<myStruct>&);
#endif // HEADER_H_INCLUDED
function.cpp
#include <iostream>
#include <vector>
#include "header.h"
using namespace std;
void myFunction(vector<myStruct>& myVec){
myVec.push_back(myStruct());
myVec[0].typeInt=5;
cout<<myVec[0].typeInt<<endl;
}
Right now, this works for what I need it to do. Unfortunately, I'm told I cannot define struct myStruct inside header.h but instead must have it within main() in main.cpp.
I've tried changing my code to the following (function.cpp unchanged):
main.cpp v2
#include <iostream>
#include "header.h"
using namespace std;
int main()
{
struct myStruct{
int typeInt;
string typeString;
double typeDouble;
};
vector<myStruct> myVec;
myFunction(myVec);
return 0;
}
header.h v2
#ifndef HEADER_H_INCLUDED
#define HEADER_H_INCLUDED
#include <vector>
using namespace std;
template <typename myStruct>
void myFunction(vector<myStruct>&);
#endif // HEADER_H_INCLUDED
Now I receive the error:
error: 'myStruct' was not declared in this scope on line 7 of function.cpp.
How can I use myStruct in function.cpp, while still defining myStruct in main() of main.cpp?
this way using template is correct, that problem occur in function.cpp right？
you try to define the function "myFunction(..)" in header.h,
and remove function.cpp, this program will work well.
if you must implement that fuction in function.cpp, you have to create a template class.
I am unsure about the use of separate files for classes. How do I make functions inside the classes? Where do I put it?
QuizMain.cpp:
#include "QuizMain.h"
#include <iostream>
#include <string>
using namespace std;
QuizMain::QuizMain()
{
// Hia stackoverflow
}
QuizMain.h file:
#ifndef QUIZMAIN_H
#define QUIZMAIN_H
#include <string>
using namespace std;
class QuizMain
{
public:
QuizMain();
private:
};
#endif // QUIZMAIN_H
Main file:
#include <iostream>
#include <string>
#include "QuizMain.h"
using namespace std;
int main()
{
QuizMain qm;
return 0;
}
How would I make a class and call it correctly?
This is an example:
QuizMain.cpp file:
#include "QuizMain.h"
#include <iostream>
#include <string>
using namespace std;
QuizMain::QuizMain()
{
// Hia stackoverflow
}
void QuizMain::my_new_function(std::string my_name){
std::cout << "Hi " + my_name +"!" << std::endl;
}
QuizMain.h file:
#ifndef QUIZMAIN_H
#define QUIZMAIN_H
#include <string>
class QuizMain
{
public:
QuizMain();
void my_new_function(std::string my_name);
private:
};
#endif // QUIZMAIN_H
Main file:
#include <iostream>
#include <string>
#include "QuizMain.h"
using namespace std;
int main()
{
QuizMain qm;
qm.my_new_function("foo");
return 0;
}
Anyway, there is no point from asking such a question here. You should probably find a good book/resource and learn how to write and use functions.
Normally you have a header file and cpp file. The header file is where you declare your functions and member variables. The cpp file is where you implement your functions.
quizmain.h
// QuizMain.h file
#ifndef QUIZMAIN_H
#define QUIZMAIN_H
#include <string>
class QuizMain
{
public:
QuizMain(int quizScore);
// declare public functions here
private:
int quizScore; // declare private member variables here.
};
#endif // QUIZMAIN_H
cpp file
// QuizMain.cpp file
#include "QuizMain.h"
#include <iostream>
#include <string>
using namespace std;
QuizMain::QuizMain(int quizScore)
{
this.quizScore = quizScore; // init a quiz score
}
main
Call and create a class object like this
QuizMain quiz(95);
It is easy to do.
If you use the IDE project, the IDE set you to use the any file. Like code::block IDE But if you do not use the IDE project it is a little different to use.
You should write the .h file and then,after all writing you should put .cpp file.
Also you can use interface class that works by poiter.
/// .h file and declaration
#ifndef ONE.H
#define ONE.H
class one {
public:
one();
~one();
};
#include "one.cpp"
#endif ONE.H
then:
/// .cpp file and implementation
one::one(){
std::cout<<"constructor one"<<std::endl;
}
one::~one(){
std::cout<<"destructor one"<<std::endl;
}
then :
#include <iostream>
#include "one.h"
int main()
{
one o;
}
output:
constructor one
destructor one
Process returned 0 (0x0) execution time : 0.010 s
Press ENTER to continue.
How do I execute a member's function by passing the object and the member's function to another function in c++. I do understand the answer to my question is out there; however, I do not know what this is called. So far I created 2 files, exeFunc.h and exeFunc.cpp. Their code consist of:
exeFunc.h
/*
File: exeFunc.h
Header file for exeFunc Library.
*/
#ifndef EXEFUNC_H
#define EXEFUNC_H
#include "mbed.h"
#include "msExtensions.h"
#include "cfExtensions.h"
#include <map>
class exeFunc
{
public:
exeFunc(msExtensions &msExt, cfExtensions &cfExt);
private:
void _splitFuncFromCmd();
void _attachCallback();
msExtensions &_msExt;
cfExtensions &_cfExt;
//FunctionPointer _p;
};
#endif
exeFunc.cpp
/*
File: exeFunc.cpp
Execute functions in other Sensor libraries/classes
Constructor
*/
#include "mbed.h"
#include "ConfigFile.h"
#include "msExtensions.h"
#include "cfExtensions.h"
#include "exeFunc.h"
#include <map>
#include <string>
using namespace std;
exeFunc::exeFunc(msExtensions &msExt, cfExtensions &cfExt) : _msExt(msExt), _cfExt(cfExt)
{
//_cfExt.checkConfigForFirstStart();
//_p.attach(&_cfExt, &cfExtensions::checkConfigForFirstStart);
//_p.call();
}
void exeFunc::_splitFuncFromCmd()
{
}
void exeFunc::_attachCallback()
{
}
I wrote a completed example, may helps
class MyClass
{
public:
MyClass(int b)
:_b(b)
{
}
int Foo(int a)
{
return a * _b;
}
int _b;
};
typedef int (MyClass::*MFP)(int);
int get_result(MyClass* obj, MFP mfp)
{
int r = (obj->*mfp)(5); // 30
return r;
}
int _tmain(int argc, _TCHAR* argv[])
{
MFP mfp = &MyClass::Foo;
MyClass m(6);
get_result(&m, mfp);
return 0;
}
You call it by another function.if you have an independent function.
To be honesty your question is not completely clear.However :
int F(int,int,int);
int g();
//main scope
F(g(),a,b)