I am using the g++ compiler on a linux mint.
I´m tying to make a class for neural Network witch i want play tic tac toe.
My Header:
#ifndef tttAi
#define tttAi
#include <string>
class Synaps{
public:
explicit Synaps(const std::string& n, double v);
void add(double ad);
void multi(double mu);
void save();
double read();
private:
std::string name;
double Syn_value;
};
#endif
My functions are:
#include "tttAi.h"
#include <fstream>
#include <string>
Synaps::Synaps(const std::string& n, double v)
:name(n), Syn_value(v){
}
void Synaps::add(double ad) { //change by addition
Syn_value += ad;
}
void Synaps::multi(double multip) { //change by multiplication
Syn_value *= multip;
}
double Synaps::read() {
return Syn_value;
}
And here is what i wanted it to do:
#include <iostream>
#include "tttAi.h"
#include "tttAi.cpp"
int main() {
Synaps n1n6("n1n6", 75);
n1n6.multi(2);
std::cout << n1n6.read() << '\n';
/*Want it to just output the value of Syn_value Witch at
this point should be 150 if i have done everything right*/
}
Command used: g++ -Wall -std=c++14 *cpp
so what i would think i´d get was just the consol output of 150 but whilst compiling i get this endless error message:
enter image description here
hope you have a idea of what i did wrong, any ideas welcome.
You're including a cpp file containing definitions multiple times (i.e. you should not write
#include "tttAi.cpp"
in your main.cpp file) and therefore violating the ODR - one definition rule.
Remember that including a file means duplicating that file's contents in the point of inclusion (and therefore duplicating your definitions as well).
The problem seems to be #include "tttAi.cpp" in your main.cpp file.
You should not include cpp files
You should not #include .cpp files. Instead, just list them on the command line when you compile.
Related
I am reading a book (C++ for dummies) as well as watching youtube videos to learn how to code. I am currently struggling with very simple class functions.
Main.cpp
#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <string>
#include "Test.h"
using namespace std;
int x;
int main(int nNumberofArgs, char* pszArgs[])
{
combat fight;
cout << x;
fight.dodmg();
cout << x;
return 0;
}
Test.h my header file with the class
#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <string>
using namespace std;
#ifndef TEST_H_INCLUDED
#define TEST_H_INCLUDED
class combat
{
public:
int dodmg();
void zero_out();
private:
int x;
};
#endif // TEST_H_INCLUDED
Test.cpp class functions
#include "Test.h"
int combat::dodmg()
{
x = x - 5;
return x;
}
void combat::zero_out()
{
x = 20
}
I tried to make this very simplistic just to figure out how to work a class.
I included a lot of #includes just to try and make sure it wasn't something stupid like I needed strings.
I am not sure why but the videos I watched simply had the header say
ifndef TEST_H (of their respective code, mine has an _INCLUDE as well, I tried deleting it and it still didn't work.
My unfortunate errors
on line 14 of main.cpp fight.dodmg(); it says
\Beginning_Programming-CPP\Playing_with_class\main.cpp|14|undefined reference to `combat::dodmg()'|
then below that
||error: ld returned 1 exit status|
How are you compiling this? I think this is an issue because you arent compiling your Test.cpp file. If you arent already, try compiling with the command:
g++ main.cpp Test.cpp -o MyProgram
UPDATE:
Few things, you dont have a closing statement to your #ifndef directive in Text.h, you will need a constructor to set the value of x so i added one to the combat class also you were missing a semicolon in the zero_out function. I added comments to all the lines I changed.
Okay try this:
Test.h
#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <string>
using namespace std;
#ifndef TEST_H_INCLUDED
#define TEST_H_INCLUDED
class combat
{
public:
combat(); // added constructor
int dodmg();
void zero_out();
private:
int x;
};
#endif // closed #ifndef
Text.cpp
#include "Test.h"
combat::combat() // implemented constructor
{
x = 20;
}
int combat::dodmg()
{
x = x - 5;
return x;
}
void combat::zero_out()
{
x = 20; // added ';'
}
Hope this helps,
Final edit: I dont think you really need your header guards in this scenario, you could remove the "#ifndef, #define, and the #endif" lines and not see a difference really
It sounds like you provide the wrong arguments for the compiler. Your header file (Test.h) simply provides signatures for the methods, but the implementations are given in the source file (Test.cpp).
This is an important part of writing C++ (or C) code. Your compiler does not automatically search for source files, so you need to tell it where to look, e.g.:
g++ -std=c++11 main.cpp Test.cpp -o main
Hi I was just trying to learn separate Classes in C++. I don't know why my code is not working.
So here is the main file code
#include <iostream>
#include "Number.h"
using namespace std;
int main()
{
Number key;
key.setNumber(200);
cout<<key.getNumber();
return 0;
}
Here is the Class cpp functions file code
#include "Number.h"
#include <iostream>
using namespace std;
void Number::setNumber(int transfernumber)
{
privatenumber = transfernumber;
}
int Number::getNumber()
{
return privatenumber;
}
And here is the header file
#ifndef NUMBER_H
#define NUMBER_H
class Number
{
public:
Number();
void setNumber(int transfernumber);
int getNumber();
private:
int privatenumber;
};
#endif // NUMBER_H
Thanks
In your cpp file you need to define the default constructor for the Number class. For example:
Number::Number() : privatenumber(0) {}
I have test your example. The error happened for the main.cpp cannot found the number.cpp. You have three ways to solve it:
write your main() to the number.cpp, not a solo file.
complie the main.cpp with the linux command gcc or write a Makefile, instead of using codeblocks.
If you want to use the codeblocks for compiling, you should create a project, and then add your three files to the project. Now compile the main.cpp.
Use the three ways above, I think you will compile successfully.
BTW, you should add the Number::Number() 's implementation.
My program have encountered a strange error: the header files slows the program down. I test the header file with empty code ( that is : main() {} ) and it takes 40s to run that empty code.
Header files .h
#include "stdafx.h"
#include <string>
#ifndef LZ_H
#define LZ_H
extern int e,i;
extern std::string dic[1000000];
void init();
#endif
Functions file .cpp
#include "lz.h"
#include "stdafx.h"
#include <string>
std::string dic[1000000];
int i=0;
int e=0;
std::string cstr(char c)
{
return std::string(1,c);
}
void init()
{
for (e=0;e<=255;e++) dic[e]=cstr(e);
e=e-1;
}
Test main file .cpp
#include "lz.h"
void main() {}
Result: 40s.
I have never faced such strange error before.
By putting a global declarations of one million strings in the .cpp file, you are forcing the compiler to put in the code to create one million string objects when the program starts. This is the reason for your slowdown.
As you are only using the first 256 elements of the array, change it to be of size 256.
After fixing the previous problem (see my one other question that I have asked). I had declared more classes.
One of these is called CombatAdmin which does various things: (Header file)
#ifndef COMBATADMIN_H
#define COMBATADMIN_H
#include <string> // Need this line or it complains
#include <Player.h>
#include <Sound.h>
#include <Enemy.h>
#include <Narrator.h>
using namespace std;
class Enemy;
class Player;
class CombatAdmin // Code yet to be commented here, will come soon.
{
public:
CombatAdmin();
void healthSet(double newHealth, string playerName);
void comAdSay(string sayWhat);
void playerFindsChest(Player *player,Weapon *weapon,Armour *armour);
void youStoleOurStuffEncounter(Player *player);
void comAdWarning(string enemyName);
void comAdAtkNote(string attack, double damage,string target,string aggresor);
void entDefeated(string entName);
void comAdStateEntHp(string ent, double hp);
void comAdStateScanResults(string enemyName, double enemyHealth);
string doubleToString(double number);
string intToString(int number);
bool isRandEncounter();
void randomEncounter(Player *player,Sound *sound,Narrator *narrator);
bool combatRound(Player *player, Enemy *enemy, Sound *sound, bool ran);
void playerFindsItem(string playerName,string itemName,double itemWeight,double playerWeight);
void playerFindsGold(string playerName,double coinCnt,double playerCoinCnt);
};
#endif // COMBATADMIN_H
It is then instanced in the main.cpp file like this: (Snippet of the main.cpp file)
#include <iostream> // Required for input and output
#include <Item.h> // Item header file.
#include <Weapon.h> // Header files that I have made for my classes are needed for this program
#include <sstream> // Needed for proper type conversion functions
#include <windows.h> // for PlaySound() and other functions like sleep.
#include <time.h> // Needed to seed the rand() function.
#include <mmsystem.h> // Not sure about this one, possibly defunct in this program.
#include <stdio.h> // Needed for a similar kind of output as iostream for various functions error msgs.
#include <irrKlang.h> // The header file of the sound lib I am using in this program.
#include <Narrator.h> // The narrators's header file.
#include <Pibot.h> // Other header files of classes.
#include <Armour.h>
#include <Player.h>
#include <Weapon.h>
#include <CombatAdmin.h>
using namespace irrklang;
using namespace std;
// Forward referenced functions
void seedRandom(); // Seeds the random number so it will be random as apposed to pseudo random.
string getPlayerName(string temp); // Gets the player's new name.
int main(int argc, char* argv[])
{
// Variables and object pointers declared here.
CombatAdmin *comAd = new CombatAdmin(); // Handles combat.
Narrator *narrator = new Narrator(); // The Narrator that says stuff
Pibot *piebot = new Pibot(); // PIbot, the player's trusty companion
string temp; // Temp string for input and output
However, when I try to compile the project, I get the following error:
C:\Documents and Settings\James Moran.HOME-B288D626D8\My Documents\C++ projects\Test Project\main.cpp|59|undefined reference to `CombatAdmin::CombatAdmin()'|
I am using the Code::Blocks IDE (ver 10.05), with the GNU GCC compiler. The project is of type "Console application". I am using windows XP 32 bit SP3.
I have tried changing to search directories to include where the object files are, but no success there.
As can be seen from the code, the narrator and PIbot are instanced just fine. (then used, not shown)
My question is, therefore, what do I need to do to stop these errors occurring? As when I encountered similar "Undefined reference to x" errors before using libraries. I had just forgotten to link to them in Code::Blocks and as soon as I did, they would work.
As this class is of my own making I am not quite sure about this.
Do say if you need more information regarding the code etc.
You have declared the default constructor (CombatAdmin()) and thus prevented the compiler from automatically generating it. Thus, you either need to 1) remove declaration of the default constructor from the class, or 2) provide an implementation.
I had this kind of error and the cause was that the CombatAdmin.cpp file wasn't selected as a Build target file: Prject->Properties->Build targets
Are you sure you've to include your header as:
#include <CombatAdmin.h>
?
I think you need to include your header file as:
#include "CombatAdmin.h"
And same for other headers written by you, like these:
#include "Armour.h"
#include "Player.h"
#include "Weapon.h"
//and similarly other header files written by you!
See this topic:
What is the difference between #include <filename> and #include "filename"?
My solution was just to add a line in the header before the class defenition:
class CombatAdmin;
I am writing a class and need to separate the declarations from the implementation, but I keep receiving "undefined reference" errors when compiling and linking my test program. It works fine when I include the implementation in the .h file, so I believe I am doing something wrong in there. I just can't figure out what.
Huge_Integer.h
#ifndef HUGE_INTEGER_H
#define HUGE_INTEGER_H
#include <vector>
#include <string>
using namespace std;
class Huge_Integer
{
public:
Huge_Integer();
Huge_Integer(string);
void input();
string output();
void add(Huge_Integer);
void subtract(Huge_Integer);
bool is_equal_to(Huge_Integer);
bool is_not_equal_to(Huge_Integer);
bool is_greater_than(Huge_Integer);
bool is_less_than(Huge_Integer);
bool is_greater_than_or_equal_to(Huge_Integer);
bool is_less_than_or_equal_to(Huge_Integer);
private:
vector<int> value;
};
#endif
Huge_Integer.cpp
#include<vector>
#include<string>
#include<iostream>
#include "Huge_Integer.h"
using namespace std;
// all stubs for now...
Huge_Integer::Huge_Integer()
{
cout << "object created\n";
}
Huge_Integer::Huge_Integer(string s)
{
cout << "object created\n";
}
//etc...
It also works if I put #include "Huge_Integer.cpp" in my test file, but I shouldn't have to do that, right?
I am using MinGW.
Thanks in advance!
Edit: Added stubs from my .cpp file
Sounds like a linking issue.
What that means is that you have to compile your class first -- this will create a compiled object file.
Then compile the main program while passing in this compiled version of the class.
Like this:
g++ -c huge_integer.cpp
g++ main.cpp huge_integer.o
Substitute your mingw command for g++ if it is different.
Not related to linking, but you are referring to Huge_Integer inside the class declaration itself.
At least with g++, you should add a forward declaration before so that Huge_Integer has meaning inside the class declaration thus:
class Huge_Integer; // forward declaration
class Huge_Integer {
Huge_Integer();
// etc...
void add(Huge_Integer);
Note: I don´t have comment privileges, so I had to type in the answer box.