Won't compile, can YOU compile it on your compiler?

Quote:

---

// Listing 15.7
//demonstrates use of an array of pointers to functions

#include <iostream>
using namespace std;

void Square (int&,int&);
void Cube (int&, int&);
void Swap (int&, int &);
void GetVals(int&, int&);
void PrintVals(int, int);

int main()
{
int valOne=1, valTwo=2;
int choice, i;
const MaxArray = 5;
void (*pFuncArray[MaxArray])(int&, int&);

for (i=0;i<MaxArray;i++)
{
cout << "(1)Change Values (2)Square (3)Cube (4)Swap: ";
cin >> choice;
switch (choice)
{
case 1: pFuncArray[i] = GetVals; break;
case 2: pFuncArray[i] = Square; break;
case 3: pFuncArray[i] = Cube; break;
case 4: pFuncArray[i] = Swap; break;
default:pFuncArray[i] = 0;
}
}

for (i=0;i<MaxArray; i++)
{
if ( pFuncArray[i] == 0 )
continue;
pFuncArray[i](valOne,valTwo);
PrintVals(valOne,valTwo);
}
return 0;
}

void PrintVals(int x, int y)
{
cout << "x: " << x << " y: " << y << endl;
}

void Square (int & rX, int & rY)
{
rX *= rX;
rY *= rY;
}

void Cube (int & rX, int & rY)
{
int tmp;

tmp = rX;
rX *= rX;
rX = rX * tmp;

tmp = rY;
rY *= rY;
rY = rY * tmp;
}

void Swap(int & rX, int & rY)
{
int temp;
temp = rX;
rX = rY;
rY = temp;
}

void GetVals (int & rValOne, int & rValTwo)
{
cout << "New value for ValOne: ";
cin >> rValOne;
cout << "New value for ValTwo: ";
cin >> rValTwo;
}

---

Ok it's been 3 consecutives example from the book that won't compile.....this is an example from STYC++ in 21 Days......Does it compile on your compiler.....by the way I see the problem in it I just want to know.const MaxArray = 5; <-- no return value declared......

I'll just include the file it doensn't show up good because of the vcode tags or something.

Sorry I am having problems with attaching this thing here it goes......hopefully.

Might just be a typo, especially if you are reading from an online book.

Did it compile on yours? I am using STYC++ in 21 Days and I downloaded the source code.......if it works for you tell me what compiler you're using.

I think I may have found the culprit:


switch (choice)
{
case 1: pFuncArray = GetVals; break;
case 2: pFuncArray[i] = Square; break;
case 3: pFuncArray[i] = Cube; break;
case 4: pFuncArray[i] = Swap; break;
defaultFuncArray[i] = 0;
}
}

LOL, just joking with you

Doesn't compile.

What compiler are you using?

Dev-C++ (actually mingw for the technical people)

Well I just tried this......

Code:

---


//Listing 15.10 Pointers to member functions using virtual methods

#include <iostream.h>


class Mammal
{
public:
        Mammal():itsAge(1) {  }
        virtual ~Mammal() { }
        virtual void Speak() const = 0;
        virtual void Move() const = 0;
protected:
        int itsAge;
};

class Dog : public Mammal
{
public:
        void Speak()const { cout << "Woof!\n"; }
        void Move() const { cout << "Walking to heel...\n"; }
};


class Cat : public Mammal
{
public:
        void Speak()const { cout << "Meow!\n"; }
        void Move() const { cout << "slinking...\n"; }
};


class Horse : public Mammal
{
public:
        void Speak()const { cout << "Winnie!\n"; }
        void Move() const { cout << "Galloping...\n"; }
};


int main()
{
        void (Mammal::*pFunc)() const =0;
        Mammal* ptr =0;
        int Animal;
        int Method;
        bool fQuit = false;

        while (fQuit == false)
        {
                cout << "(0)Quit (1)dog (2)cat (3)horse: ";
                cin >> Animal;
                switch (Animal)
                {
                case 1:        ptr = new Dog; break;
                case 2: ptr = new Cat; break;
                case 3: ptr = new Horse; break;
                default: fQuit = true; break;
                }
                if (fQuit)
                        break;

                cout << "(1)Speak  (2)Move: ";
                cin >> Method;
                switch (Method)
                {
                case 1: pFunc = Mammal::Speak; break;
                default: pFunc = Mammal::Move; break;
                }

                (ptr->*pFunc)();
        delete ptr;
        }
        return 0;
}

---

and it wouldn't compile on DevC++ but once I tried it on Borland it worked.

--------------------------------------------------------------------------
Editted because I didn't read thoroughly enough.
--------------------------------------------------------------------------

Some compilers require you to be explicit when using the address of a function. This works on Dev C++ -

Code:

---

#include <iostream>

using namespace std;

class Mammal
{
public:
        Mammal():itsAge(1) {  }
        virtual ~Mammal() { }
        virtual void Speak() const = 0;
        virtual void Move() const = 0;
protected:
        int itsAge;
};

class Dog : public Mammal
{
public:
        void Speak()const { cout << "Woof!\n"; }
        void Move() const { cout << "Walking to heel...\n"; }
};


class Cat : public Mammal
{
public:
        void Speak()const { cout << "Meow!\n"; }
        void Move() const { cout << "slinking...\n"; }
};


class Horse : public Mammal
{
public:
        void Speak()const { cout << "Winnie!\n"; }
        void Move() const { cout << "Galloping...\n"; }
};


int main()
{
        void (Mammal::*pFunc)() const =0;
        Mammal* ptr =0;
        int Animal;
        int Method;
        bool fQuit = false;

        while (fQuit == false)
        {
                cout << "(0)Quit (1)dog (2)cat (3)horse: ";
                cin >> Animal;
                switch (Animal)
                {
                case 1:        ptr = new Dog; break;
                case 2: ptr = new Cat; break;
                case 3: ptr = new Horse; break;
                default: fQuit = true; break;
                }
                if (fQuit)
                        break;

                cout << "(1)Speak  (2)Move: ";
                cin >> Method;
                switch (Method)
                {
                case 1: pFunc = &Mammal::Speak; break;
                default: pFunc = &Mammal::Move; break;
                }

                (ptr->*pFunc)();
        delete ptr;
        }
        return 0;
}

---

Oh I see, cool.....thanks for the help.