getting syntax error !!

[ahakrush]

hey, i have been writing this code (C++) in the last week,
i have many classes in the .h file, but one problem with one class, which is:
__________________________________________________ _________

35 template <int size=10>
36 class Picture
37 {
38 vector<Shape*> vec;
39
40 public:
41 void add(Shape* s)
42 {
43 if (s != NULL) vec.push_back(s);
44 return;
45 }
46 Picture();
47 ~Picture();
48 void print_all();
49 void add(unsigned int i, Shape* s);
50 void remove(unsigned int i);
51 void print(unsigned int i);
52 void extend_all(int i);
53 void extend(unsigned int i, int x);
54 void move_all(int x, int y);
55 void move(unsigned int i, int x, int y);
56 };
__________________________________________________ __________

when trying to build i'm getting this errors:
1>c:\users\ahmad\desktop\shapes\shapes\shapes.h(38 ): error C2143: syntax error : missing ';' before '<'
1> c:\users\ahmad\desktop\shapes\shapes\shapes.h(56) : see reference to class template instantiation 'Picture<size>' being compiled
1>c:\users\ahmad\desktop\shapes\shapes\shapes.h(38 ): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\users\ahmad\desktop\shapes\shapes\shapes.h(38 ): error C2238: unexpected token(s) preceding ';'

[Banfa]

It's hard to say without the rest of the file but here are some clues

• Where is Shape defined, it needs to be earlier in the file than this class?
• Have you included vector into this file?
• Do you have a using namespace std; in the file? You shouldn't it is not good practice but if you haven't you need to declare your vector std::vector.

[ahakrush]

here's how the code starts:

#include <vector>
using namespace std;
 
template <class T> 
class Point
{
public:
    T x;
    T y;
    Point(T _x=0, T _y=0): x(_x), y(_y){}
    void move(T _X, T _y)
    {
        x += _X;
        y += _y;
    }
};
/******************************************************/
class Shape
{
public:
    virtual void print()=0;
    virtual Shape* clone()=0;
    virtual void extend(int i)=0;
    virtual void move(int x,int y)=0;
};
/******************************************************/
template <int size=10>
class Picture
{
    vector<Shape*> vec;
 
public:
    void add(Shape* s)
    { 
        if (s != NULL) vec.push_back(s);
        return;
    }
    Picture();
    ~Picture();
    void print_all();
    void add(unsigned int i, Shape* s);
    void remove(unsigned int i);
    void print(unsigned int i);
    void extend_all(int i);
    void extend(unsigned int i, int x);
    void move_all(int x, int y);
    void move(unsigned int i, int x, int y);
};
/******************************************************/
template <class X>
class Circle: public Shape 
{
protected:
    X radius;
    Point<X> center;
    static const X step; 
 
public:
    Circle();
    Circle(X, X, X); 
    Circle(Point<X>, X);
    virtual void print();
    virtual Circle<X>* clone();
    virtual void extend(int i);
    virtual void move(int x,int y);
};
/******************************************************/
template <class X>
class Square: public Shape 
{
protected:
    Point<X> point;
    X limp;
    static const X step;
 
public:
    Square();
    Square(X, X, X);
    Square(Point<X>, X);
    virtual void print();
    virtual Square<X>* clone();
    virtual void extend(int i);
    virtual void move(int x, int y);
};
/******************************************************/
template <class X>
class Triangle: public Shape 
{
private:
    Point<X> head_1, head_2, head_3;
    static const X step;
 
public:
    Triangle();
    Triangle(X, X, X, X, X, X);
    Triangle(Point<X>, Point<X>, Point<X>);
    void print();
    void extend(int i);
    Triangle<X>* clone();
    void move(int x, int y);
};
/******************************************************/
template <class X>
class Ellipse: public Circle<X>
{
protected:
    X radius_2;
 
public:
    Ellipse();
    Ellipse(X, X, X, X);
    Ellipse(Point<X>, X, X);
    void print();
    Ellipse<X>* clone();
    void extend(int i);
    void move(int x, int y);
};
/******************************************************/
template <class X>
class Rectangle: public Square<X>
{
private:
    X vertical;
 
public:
    Rectangle();
    Rectangle(X, X, X, X);
    Rectangle(Point<X>, X, X);
    void print();
    Rectangle<X>* clone();
    void extend(int i);
    void move(int x, int y);
};
/******************************************************/
 

i didn't use #include<vector> and using namespace std;, then the compiler gave the errors in first post.
now, after adding these (#include<..> and using namespace..) it gives linker errors !

here are the errors:
1>shapes.obj : error LNK2001: unresolved external symbol "private: static char const Triangle<char>::step" (?step@?$Triangle@D@@0DB)
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: __thiscall Picture<6>::~Picture<6>(void)" (??1?$Picture@$05@@QAE@XZ) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: void __thiscall Picture<6>::add(unsigned int,class Shape *)" (?add@?$Picture@$05@@QAEXIPAVShape@@@Z) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: __thiscall Triangle<int>::Triangle<int>(int,int,int,int,int,i nt)" (??0?$Triangle@H@@QAE@HHHHHH@Z) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: void __thiscall Picture<6>::extend_all(int)" (?extend_all@?$Picture@$05@@QAEXH@Z) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: void __thiscall Picture<6>::remove(unsigned int)" (?remove@?$Picture@$05@@QAEXI@Z) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: void __thiscall Picture<6>::move(unsigned int,int,int)" (?move@?$Picture@$05@@QAEXIHH@Z) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: void __thiscall Picture<6>::move_all(int,int)" (?move_all@?$Picture@$05@@QAEXHH@Z) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: void __thiscall Picture<6>::print(unsigned int)" (?print@?$Picture@$05@@QAEXI@Z) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: void __thiscall Picture<6>::print_all(void)" (?print_all@?$Picture@$05@@QAEXXZ) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: __thiscall Triangle<char>::Triangle<char>(void)" (??0?$Triangle@D@@QAE@XZ) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: __thiscall Picture<6>::Picture<6>(void)" (??0?$Picture@$05@@QAE@XZ) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: __thiscall Rectangle<long>::Rectangle<long>(class Point<long>,long,long)" (??0?$Rectangle@J@@QAE@V?$Point@J@@JJ@Z) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: __thiscall Square<unsigned int>::Square<unsigned int>(unsigned int,unsigned int,unsigned int)" (??0?$Square@I@@QAE@III@Z) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: __thiscall Ellipse<double>::Ellipse<double>(class Point<double>,double,double)" (??0?$Ellipse@N@@QAE@V?$Point@N@@NN@Z) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: __thiscall Circle<char>::Circle<char>(char,char,char)" (??0?$Circle@D@@QAE@DDD@Z) referenced in function _main
1>shapesMain.obj : error LNK2019: unresolved external symbol "public: __thiscall Circle<int>::Circle<int>(void)" (??0?$Circle@H@@QAE@XZ) referenced in function _main

and here's my main:

#include <iostream>
#include "shapes.h"
 
 
template<> const int Circle<int>::step = 1;
template<> const double Circle<double>::step = 0.1;
 
template<> const int Square<int>::step = 1;
template<> const double Square<double>::step = 0.1;
 
template<> const int Triangle<int>::step = 1; 
template<> const double Triangle<double>::step = 0.1;
 
 
int main()
{
    Circle<int> *c = new Circle<int>();
    c->print();
    Circle<char> *ch = new Circle<char>('2','3','3');
    ch->print();
    Ellipse<double> *e = new Ellipse<double>(Point<double>(1,2),2.2,5.6);
    e->print();
    Square<unsigned int> *s = new Square<unsigned int>(3,4,5);
    s->print();
    Rectangle<long> *r = new Rectangle<long>(Point<long>(1,3),2,3);
    r->print();
    cin.get();
     Picture<6> pic;
 
    pic.add(c);
    pic.add(e);
    pic.add(ch);
    pic.add(s);
    pic.add(r);
    delete c;
    delete ch;
    delete e;
    delete s;
    delete r;
    pic.add(new Triangle<char>());
    pic.print_all();
    pic.print(2);
    pic.move_all(20,3);
    pic.move(2,5,6);
    pic.remove(3);
    pic.print_all();
    pic.extend_all(-2);
    pic.add(4,new Triangle<int>(2,3,4,4,5,5));
 
    return 0;
}
 

[weaknessforcats]

Declaring a static variable inside a class does not create the variable.

Remember that a static variable is not a member variable. it has no this pointer. That's so that you don't create another static variable each time you create a class object.

You will need to create your static variable outside the class template.

[ahakrush]

thank your for your response,
but you mean by "outside the class template" ??, each class has its own "step", e.g Circle<int> has its step which is 1, and Circle<double> has another one, which is 0.1
sorry but i'm new for C++, so can you please explain more :)

[weaknessforcats]

There can be only one static variable named step for all of your objects. Every object you create will use the same static variable. This appears to not meet your needs.

Therefore, don't use a static variable.

Since each class has its own step, then just make the step a regular member variable. Use a constructor to inialize the variable.

Since your variable is const, then you need to initialize it by using the initialization list of your constructors.

You could pass the step value to the constructor when you create the object:

Circle<double> cir(0.1);
Circle<int> anothercir(1);

You might consider using an enum for the step rather than a template paramter type.

[ahakrush]

ok thank you very, :)
i have fixed it :)